#help-with-linux-sbcs

1 messages · Page 26 of 1

half nexus
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And then came the pi shortage

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I can buy anything but the pi itself

hardy plaza
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I think the problem (if the question is getting it into a thin package like a gum packet) is that you'd have to avoid using the GPIO pins since that's 12mm right there. The little PiTFT display isn't actually any thicker than the Pi Zero itself, so if you used wire to connect the two side by side you could keep the thickness to around 5mm.

amber fulcrum
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aaaah i see, that makes sense, i don't really have a good idea of what size a gum packet is because it really varies in the UK, the gum i buy comes loose in a box for example

hardy plaza
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As an experiment I built a Pi Zero W and its tiny spy camera into a hollowed-out paperback book, with the camera on the spine. Very MI6-ish 😎 . I wired it for USB power but there would have been room for a small LiPo battery. The one issue with any of these kinds of installations that bears consideration is heat. If a Pi Zero W is not vented it will get pretty hot, pretty quickly.

hardy plaza
amber fulcrum
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are Pi Zero W's pretty good? ive been looking to pick up a Pi eventually, but student budget and all they're kinda expensive for me

hardy plaza
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They're great little boards. The Pi Zero 2 W is a quad-core version with 512MB of memory, with WiFi for US$15. So if you can work in a relatively memory-constrained environment you still get multiple cores (whereas the other two Pi Zeros are single core).

Of course the biggest issue is that it's likely nobody will be buying any non Pi 4 models (any of the older 40nm silicon) aren't available at all, perhaps for as long as 52 weeks last I heard.

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But where else can you get a proper Linux computer for $15?

amber fulcrum
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I think i have a couple of Pi 2's around that i bought when i was a kid, but i've not really found a use for older Pi's

hardy plaza
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If you use a Pi Zero as a console rather than desktop computer and remote ssh into it, it's often hard to tell you're not actually on a much larger Linux server. Great for those wanting to learn Linux, or programming or computer use on the command line. A bit limited with a desktop as you're kinda pushing the performance boundaries IMO. Though it does actually work fine, just a bit slow. No YouTube videos or Grand Theft Auto.

amber fulcrum
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oooh good to know!! i don't really have any specific uses in mind for one yet, but it seems like such a neat little device that im sure i'd come up with something

hardy plaza
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Yeah, we kinda take things like this for granted a bit, but they're really remarkably great little devices. I'm a big fan of the Pi Zero, have used them for lots of things, even put one inside my letterbox so I can see if I have any mail. It has a magnetic door sensor and an IR human detector which turns on a string of LEDs to light up the path at the front of the house (and thusly deters burglars methinks).

amber fulcrum
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is the Pi Zero W 2 much of an upgrade?? i notice the 1 is a lot easier to get a hold of

hardy plaza
hardy plaza
amber fulcrum
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oop my message disappeared

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imma have to check back in a week or two and see if my UK supplier stocks them!!

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cause it's a cool little kit

hardy plaza
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I don't see them on the Pimoroni web site right now, wonder if they've been discontinued.

amber fulcrum
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they;re out of stock on pimoroni but i use uhh

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Pi hut

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sometimes, because they tend to stock stuff that pimoroni doesn't have

hardy plaza
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If you're looking for Raspberry Pis there aren't any, anywhere. I think Pi 4s are sometimes found, and Pi 400s. But the chip shortage has hit.

amber fulcrum
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Oh yeah that's fair, Pihut tends to stock little things like the octocam type kits or arduino stuff, as well as the microbit

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i like browsing it sometimes

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they do sometimes list stuff that's just not in stock for a while though, still waiting to see if they get a lock picking kit back in stock

hardy plaza
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It's kinda sad when the Pi Hut has no Pi.

amber fulcrum
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a little!! i think the only Pi i can get from them is a 2gb 4b or a Pi Zero W 1

hardy plaza
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Ah, yes. That's probably the only Raspberry Pi Zero W in the world right now.

amber fulcrum
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gosh is it everything that's rare right now?? i assumed it was just the big models

hardy plaza
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Actually, the Pi 4s are somewhat still available. It's all the older models that can't be found.

amber fulcrum
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oh huh! i guess i didn't keep too up to date with the shortage, most of what i know was talking to the lab techs, they're trying to get a Pi Cluster going for the uni to use

last bramble
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anything i can use as a battery

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for a portable deck

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would a standard power bank with usb C be enough

amber fulcrum
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I've seen decks with a couple of 26,000mAh power banks before, but it totally depends on ur usage

faint sparrow
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what's a deck, duck.

turbid rivet
last bramble
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ill buy one from anker in that case

amber fulcrum
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also thanks for bringing up decks!! i haven't thought about one in ages and now im writing a parts list :P

last bramble
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its basically a tiny deck

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look up the pi cyberdeck

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its a good example of what im trying to refer to

amber fulcrum
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what kind of screen are you thinking about using?

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The official Pi 7" one is verrry tempting

faint sparrow
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deck the halls

last bramble
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@amber fulcrum

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this one

amber fulcrum
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ooooh i see

mystic light
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most USB power banks timeout and cut off if their current draw is too low. I found one vendor Voltaic Systems that makes USB battery packs that are "always on"

amber fulcrum
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Anker has a mode for low power devices like headphones

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on some of their power banks

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so im wondering if one of those would be suitable

rotund pivot
amber fulcrum
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That’s pretty cool but I don’t think I can get one here sadly

rugged kettle
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Weird question, how can I take an iso image on an rpi via ssh? Due to ✨ reasons ✨ the SD card is currently difficult to get to

umbral sable
digital scroll
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Question so i'm trying to enable ssh on the raspberry pi imager and when i click use password authentication it doesnt allow me to put in a password so when i go to set it up on command prompt i have no idea what to put as the password

vapid python
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Try the default user: pi pswd: raspberry

digital scroll
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now its saying it cant find a host name

vapid python
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After you login?

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Add your new hostname to /etc/hosts

digital scroll
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asked if i wanted to put it under ecdsa, hit yes and now it wont let me type a password

fickle shard
amber fulcrum
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https://thepihut.com/products/5-800x480-tft-raspberry-pi-dsi-touchscreen-compatible-with-raspberry-pi-3b-3b-4b

The Pi Hut
5'' 800x480 TFT Raspberry Pi DSI Touchscreen (Compatible with Raspb...

This is a 5" Raspberry Pi LCD touchscreen with 800*480 resolution and 108×64.8mm display area. The product supports the Raspberry Pi DSI display interface and comes with a capacitive touch panel on its screen and supports 5 touchpoints. Features Capacitive Touchscreen, Support 5 TouchPoints. Raspberry DSI Direct Driver

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Has anyone used a screen like this before?

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The only connection to the Pi I can see on it is via ribbon cable? and I can’t tell if that’s the only connection I’d need

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I haven’t actually used a Pi yet (waiting on it to be delivered)

hardy plaza
amber fulcrum
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Oh nice!! I didn’t know it could supply enough power for a display like that, I saw a bigger one that needed a separate power connection so I was concerned

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thanks

hardy plaza
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I've used only SPI and HDMI displays myself but the DSI interface is native Pi and should work fine.

amber fulcrum
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I was thinking of plugging in an e-ink display alongside this so I could have a no-power weather display so I wanted to make sure I wasn’t using any conflicting pins or anything

hardy plaza
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You may note that the "touch screen" has only 5 touch points so it won't be functioning as a typical touch screen.

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The e-ink displays probably are SPI?

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I believe you can have as many as two SPI devices on a Pi. But since this display is DSI it's not taking up an SPI address anyway.

amber fulcrum
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Yeah the one I’m looking at is just a

https://thepihut.com/products/1-02-e-ink-display-module

The Pi Hut
1.02" E-Ink Display Module (128x80)

This is a tiny 1.02" E-Ink display module with a 128×80 resolution and embedded controller. The module communicates via an SPI interface (making it great for a number of different development boards such as the Raspberry Pi) and supports partial refresh. Due to the advantages like ultra-low power consumption, wide view

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So I assume it’s just GPIO pins and a library

hardy plaza
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Also, the doc page notes that the display will take up to 1.5A while operating so you'll need a power supply that can handle the combined current of all your devices.

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e-ink displays typical take very low power.

amber fulcrum
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fair, I was thinking of using a 26,850mA power pack I had laying about?

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Oh wait that should not be a 5

hardy plaza
amber fulcrum
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oh right yeah it’s 2.1A

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I was honestly more worried about charge time, I forgot about capacity 😅

hardy plaza
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So, you'd add up the max current of your Pi and all your devices and add about 20% for safety' sake.

amber fulcrum
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Ah yeah that’s probably an issue since I think the Pi is like, 1.5A max

hardy plaza
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If your power supply isn't capable of supplying enough juice it will brown out, dropping voltage until the Pi resets. A Pi actually needs 5.1 volts so a 5 volt supply, while it works, is already a bit lower than what is ideal.

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The official Raspberry Pi power supplies are 5.1 volts, but clearly a lot of people use 5v USB power supplies, and so long as they're beefy enough they generally work. But I'd say a significant majority of problems people report here are due to power supply issues.

amber fulcrum
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I guess I might have to look for a smaller display, not sure any powerbank I can find will be happy with the display

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Oh hold on

hardy plaza
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Or if it's okay with your requirements, find one that has a separate power jack. Then the Pi isn't affected by the display, it just sends signals.

amber fulcrum
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Where did you get 1.5A from?

hardy plaza
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The wiki page for the display.

amber fulcrum
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hmm the pi store lists 320mA as it’s maximum operating

hardy plaza
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The FAQ section: "Please check Raspberry Pi’s power. The current of the touchscreen should be at least 1.5A during its work."

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Yeah, I see that. A bit of a contradiction clearly.

amber fulcrum
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Curious

hardy plaza
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I sometimes find DFRobot's stuff a bit mystifying.

amber fulcrum
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I wonder if it’s talking about like, the current of the Pi and the Display?

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The pi seems to like to chug on 1.3A

hardy plaza
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That's not what it says but maybe that's what they mean. But that would depend entirely on the Pi. A Pi Zero has a very much smaller power requirement than a Pi 4.

amber fulcrum
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Would the display be able to pull 1.5A from the Pi even

hardy plaza
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Yeah, in theory.

amber fulcrum
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huh okay

hardy plaza
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But that does sound dodgy I agree.

amber fulcrum
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I might see if I can find any mention about it online,

hardy plaza
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I don't know what the maximum current the DSI can supply. I'm sure that'll be in the Raspberry Pi specifications somewhere though.

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Yeah, search on "raspberry pi dsi maximum current"

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Interestingly, it says "the DSI ports power lines are dimensioned ONLY for the power requirement of the camera logic NOTHING ELSE!"

amber fulcrum
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hmmm

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I might see if I can get a waveshare display or something instead

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This one seems way dodgy

hardy plaza
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Furthermore (same page):

"The PMIC chip appears capable of supplying 3V3 at 1A5 though whether it can or not on a Pi is unknown to me. That 3V3 goes to other parts of the boards, and I would expect to the SoC and other components not shown on the reduced circuit, so it is difficult to say how much current can be drawn from 3V3 on a Pi.

We don't know how much the PMIC can actually supply, we don't know how much the board uses, and that will vary depending on use, so we don't know what capacity is spare, and that will be reduced if cameras, displays and other things are connected. The amount one can draw from any 3V3 pin is not officially stated anywhere."

amber fulcrum
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This one looks a bit easier to work with 😅

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It also uses the ribbon cable surprisingly

hardy plaza
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On the other hand, if "bulk" isn't an issue for you, you might consider an HDMI display. You can plug a Pi into any HDMI display but there are some smaller ones available and the display quality will be very high. And they generally will have their own power supply.

amber fulcrum
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unfortunately bulk is an issue

hardy plaza
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yeah, the HDMI cables are undeniably bulky.

amber fulcrum
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yeah it’s a shame because I’d rather use a HDMI, but the ribbon cable seems to be an easy out for me

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they’re saying the display is 700mA ~ 750mA

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which unfortunately cuts it close for me mmm

hardy plaza
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I guess you can go with the notion that they're selling this as a functional product, so hopefully it just works.

amber fulcrum
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yeah that would be ideal

hardy plaza
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It looks like the DFRobot and PiHut are the same display, same "5-point touchscreen" it seems. It looks like the PiHut one is sourced from Waveshare, who I've bought a robot kit from.

amber fulcrum
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yeah, the 5 point is kinda weird to work with

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I’d honestly rather just not have a touch screen

hardy plaza
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Their robot kits are well made so I'd say the Waveshare stuff is likely generally pretty good.

hardy plaza
amber fulcrum
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I’m wondering if the Ada fruit one is worth going with since the documentation is just. Better

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They even list current draw with the backlight at half settings but I’d have to contend with the bulky hdmi

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And I imagine even less than the other ones because it’s not capacitive

hardy plaza
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One thing about HDMI is that your cable may be bulky but it's durable. Ribbon cables are very fragile, as are the Pi's on-board connectors. That may not be an issue for your application, but you don't want to be connecting and disconnecting the ribbon cable a lot.

amber fulcrum
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that’s a fair point, especially because I’d rather not open up the box to have to fix stuff like that, and it might get moved around a lot

hardy plaza
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The little black DSI lock bracket is very prone to snapping. I've broken a couple myself.

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I think the ribbon cable is fine for permanent installations inside of enclosures, a once-applied kind of thing. Not at all suitable for portable applications or anywhere the ribbon cable may be under any stress at all.

amber fulcrum
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that makes sense, portable is the goal for me so

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This is the box I’m planning on using

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It’s 316x195x53mm

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The main constraint for me is vertical size

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but I wanna work with it

hardy plaza
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I'm guessing that 53mm is the external height dimension, not the internal?

amber fulcrum
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Thinking of spray painting it some garish colours too, like neon pink

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Internal

hardy plaza
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ah

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then plenty of room.

amber fulcrum
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External is 59mm

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yeah? It’s hard to visualise the size for me to be honest

hardy plaza
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What all are you trying to fit inside? That's a pretty big box.

amber fulcrum
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A Pi, the screen, a power bank, an E-ink display, and maybe some funky switches and buttons

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Oh and a 30mm fan

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Oh a keyboard on the lid too

hardy plaza
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Well, one thing I've done is mock up the objects using cardboard and tape, and put them inside a container that's the planned size, shift them around to get a feel for how they'd fit.

amber fulcrum
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hmmm that’s smart, wish I hadn’t just passed over of a bunch of boxes

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also wish I hadn’t left my callipers in the lab oops

hardy plaza
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bit of cardboard and tape is all you need.

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Doesn't have to be perfectly accurate, just to give you an idea.

amber fulcrum
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maybe an 212x140x47mm ID would be more suitable then

hardy plaza
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Honestly, mock it up in cardboard and you'll have a much better idea. I don't know about you, but for me having the physical objects at hand really helps.

amber fulcrum
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It really helps me too, I just wish I had all the components in front of me for it 😅

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Little paper mock-up, I think I’m gonna have more than enough space you’re right,

AF7CCE95-8D57-4D7A-B256-BF7B97537CBB.jpg
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Keyboard could be a concern but I have a Logitech one I could slot in instead in a pinch

hardy plaza
amber fulcrum
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oooh the one with the trackpad looks nice!!

hardy plaza
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It's the keyboard I used to type directly into the console on my robots since it's radio-connected and works anywhere, and doesn't need Bluetooth.

last bramble
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are there any power bank models that work with the raspberry pi zero w

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since i was previouslytold that some power banks arent too reliable for a pi

amber fulcrum
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The solution I was given for those power banks is to solder a 100 ohm resistor across a USB cable and plug it in

wraith grove
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adding a constant draw of 50 mA, according to my potentially erroneous math

amber fulcrum
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Yeah I think that’s the minimum current that it wants to stay out of sleep mode

wraith grove
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my naive math suggests that is 0.25 watts the resistor is burning, fancier math is saying other things, but looks weird and doesn't overtly make sense to me :-)

last bramble
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i cheaped out on the power bank

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i ordered a screen, a starter kit, a power brick and the arduino starter kit

hardy plaza
# amber fulcrum The solution I was given for those power banks is to solder a 100 ohm resistor a...

Eek, that sounds like not so good an idea, especially the effect on battery life. I'm sorry I can't be more help, but a couple of years ago I had a small robot with a power bank with this problem, and I dug around on the Web until I found a circuit, which is lost in the sands of time. I still have the part I made, which has two transistors, two resistors and a cap. Plugged across 5v and ground it keeps the battery awake but at much less than 50mA.

doodad4377.jpg
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But sorry, no schematic 😑

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But if you search on "usb power bank keep alive" you'll likely find something.

amber fulcrum
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ooh okay!! If I find I have a problem with battery life I will seek this out, but for now I have some USBs with the breadboardy connectors so I can literally just slot a resistor in there as a quick fix

last bramble
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not sure what to use as a good source of battery for my raspberry pi

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want something small enough but not too small

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so that it still lasts a few hours

turbid rivet
last bramble
mystic light
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@amber fulcrum if you end up needing an 'always on' power bank, this is what I bought to power my portable microcontroller stuff: https://voltaicsystems.com/v25/

Voltaic Systems
V25 USB Battery Pack

Voltaic Systems designs high-performance solar chargers and complete power solutions for electronics and IoT applications.

amber fulcrum
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The voltaic bank does look nice, and I have been considering one, shame I can’t find a UK supplier though

wraith grove
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I wonder if a large enough capacitor can hold the fort until enough current is needed to wake the bank? Too simple?

amber fulcrum
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Maybe a film capacitor could?

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An electrolytic capacitors doesn’t hold charge for a very long time I don’t think

hardy plaza
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No capacitors hold a charge for significantly longer than others based on type, only rated capacitance. Electrolytic capacitors just happen to be a type that is available in very large sizes. But even a huge capacitor isn't going to keep a power bank awake as the bank relies on current draw, and once the capacitor is full it won't draw any further current. And it will discharge (on a curve) below the battery threshold almost immediately.

amber fulcrum
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I think the capacitor was to wake the Pi and get it to start drawing current

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Rather than wake the bank

hardy plaza
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Hmm. I don't see how that would work.

amber fulcrum
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Yeah thinking about how the bank works neither do I

wintry steeple
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does anyone know why my SenseHat on raspberry pi only sends 3 sets of data( temp, humidity and pressure) for 3 times and connection error occurs?

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im trying to send the data to adafruit io

humble marsh
mystic light
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I think power banks have a 'timeout', so if you switch on a current load every few seconds or so for ~1-10ms, maybe that would keep it from shutting off while having a very low overall power draw

amber fulcrum
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Hey so, I was thinking of using a switch to toggle my Pi on/off, how would I go about that? I haven’t got a Pi in front of me yet so I don’t understand the software too well

turbid rivet
# amber fulcrum Hey so, I was thinking of using a switch to toggle my Pi on/off, how would I go ...

For straight power on/power off, https://vilros.com/products/vilros-usb-c-5v-3a-power-supply-with-switch-designed-for-pi-4?variant=29404996698206&currency=USD&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic would just cut power. Not good for the Pi's SD/SSD, but it's the simplest way to do it.
For power on/shutdown, you would have to do some configuration software-side to enable a shutdown button. Plenty of tutorials if you google "Pi shutdown button" and browse the results. Usually a momentary switch connected to GPIO, so that the software can decide what to do with different kinds of presses in different states.

olive haven
amber fulcrum
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Ooh perfect, thanks to both of you!!

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I was looking at an SPDT or something like this

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Might end up just being the standard SPDT because looking at the dimensions that switch is bigger than my case lmao

abstract mason
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Hello Everyone, I'm using a ADS1115, and the adafruit library for it. I want to compare a value that I got from the device with an int value like 1. But it's not working, when I try to make my variable an int, the error below happens. Does anyone know what can I do? Ps: Sorry for my english..

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I've tried int(pressao), but still doesn't work

turbid rivet
abstract mason
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Already found my mistake man, thanks for your help!!!

zealous seal
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If anyones looking, looks like Microcenter has Pi 4s in stock and they require going to the story to buy them (no online ordering at all - even for pickup)

agile wigeon
mystic light
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that's the smallest by that vendor, not sure if other vendors have smaller options

blissful jolt
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anyone familiar with RP2040 C SDK? Esp about DMA I2C peripheral transfers?

unborn rapids
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When I try to start steam link on my raspberry pi 4, I get the following error message:

X11 is not supported on this version of Raspberry pi. You can run on the console or download Raspberry Pi Buster.

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Can someone help me ? 🙂

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on the Raspberry OS

amber fulcrum
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you're on bullseye right?

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i think bullseye doesn't have a feature that steamlink requires

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the Buster branch does though which is why it's asking you to run that instead

faint sparrow
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Buster is old.

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Wonder what X11 means here.

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We had XFree86, we had X.org.

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My friend rants about that new one.

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Vanity or something. ;)

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Wayland (same thing!)

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Since the RPi4 is an SOC I don't know what they did for its video capacity.

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Probably not X.org though.

amber fulcrum
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not entirely sure what it means, but it seems to have some relation to hardware acceleration?

olive haven
faint sparrow
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What you would do is stash the SD card. Get another. Install Buster on that other SD card.

hardy plaza
olive haven
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Apparently not in Bullseye, at least on the 4 -- that was the issue

west sierra
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Wait, what is it using? Wayland?

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(I mean I know it uses Wayland in Manjaro ARM)

olive haven
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Yes, Wayland "Desktops in Linux have always been based on the X Window System, usually just referred to as X. This is what provides the basic services of a window environment – drawing windows, moving them around, managing the mouse pointer and so on. But X is now very old technology – it was first released in 1984 – and while it has served admirably for nearly 40 years, some desktop environments are now using replacements. The most popular of these is a system called Wayland, which has recently become the window system used by Ubuntu.

We are still quite a long way from switching Raspberry Pi OS to Wayland, but one of its requirements is a Wayland-compatible compositing window manager, and using mutter is the first step on this path." https://www.raspberrypi.com/news/raspberry-pi-os-debian-bullseye/

hardy plaza
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This wouldn't so far as I know be different across different Pi hardware models, it is specific to the OS itself.

west sierra
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Ah, so they are using Mutter as WM.

olive haven
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Someone (@unborn rapids) above tried to run Steamlink on a 4 running Bullseye and got this message "X11 is not supported on this version of Raspberry pi. You can run on the console or downgrade to Raspberry Pi Buster." So something it wants isn't available.

hardy plaza
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This just run on a Pi 3 B+ using the latest 64 bit OS:

☻ dpkg -l |grep xserver-xorg-core 
ii  xserver-xorg-core                    2:1.20.11-1+rpt1+deb11u1         arm64        Xorg X server - core server
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...and this just run on a Pi 4 using the same 64 bit OS (same SD card):

 ☻ dpkg -l |grep xserver-xorg-core 
ii  xserver-xorg-core                    2:1.20.11-1+rpt1                 armhf        Xorg X server - core server
# 
 ☻ cat /etc/os-release
PRETTY_NAME="Raspbian GNU/Linux 11 (bullseye)"
NAME="Raspbian GNU/Linux"
VERSION_ID="11"
VERSION="11 (bullseye)"
VERSION_CODENAME=bullseye
ID=raspbian
ID_LIKE=debian
HOME_URL="http://www.raspbian.org/"
SUPPORT_URL="http://www.raspbian.org/RaspbianForums"
BUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs"
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Though it is telling that the error message uses the term "Raspbian". I don't know how hard the team has tried to expunge the old name of the OS from its strings, but it hasn't been called Raspbian for awhile now.

last bramble
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since im like one of the few people that dont own a 3d printer

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what can i use as housing

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thinking of using this old box shaped wifi router as my pi's housing

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but im not sure how inconvinient it is in comparison to just owning a 3d printer

olive haven
hardy plaza
# last bramble thinking of using this old box shaped wifi router as my pi's housing

One thing you'll probably want to consider on anything but a Pi Zero that's not under much of a workload (as they run pretty cool then), is some kind of ventilation, or some way of thermally connecting the Pi's CPU to the enclosure so it can stay cool. Unless you're running it hard you probably won't need a fan but you will need to have some even ambient airflow over the board.

amber fulcrum
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does the Pi 4 have a similar thing?

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was thinking of getting a heatsink but i could try and fudge a 25mm fan into my case

hardy plaza
# amber fulcrum does the Pi 4 have a similar thing?

If it's under any load at all a Pi 4 runs pretty hot. I'd recommend at very least heatsinks on the CPU, Ethernet controller and WiFi controller. There's cheap little three piece kits for this. A fan on its own isn't very helpful without the heatsinks — what you're doing is effectively increasing the surface area of the device so the air can cool it. The little 25mm or 30mm square fans work wonders in ventilating an enclosure.

amber fulcrum
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okay, thank you!

hardy plaza
#

those guys

amber fulcrum
#

im loookin at a very similar set

hardy plaza
#

yup.

#

The Pi 4 sets have the extra one for the USB chip.

amber fulcrum
#

glad they come self-adhesive, no idea where my thermal paste is

hardy plaza
#

Yeah, I have a small tube of that somewhere in my house, but it would probably mean tearing the house down to find it.

amber fulcrum
#

dont know if mines even in this house

#

could have gotten lost during a move

#

im thinking one of these would be nice too

#

just have to make sure i mount the fan in the right direction :P

hardy plaza
#

Actually, it doesn't matter so much, it would still do a nice job cooling, but you don't want your enclosure to act as a small vacuum cleaner. It would eventually fill with dust and cat hair.

amber fulcrum
#

aah right, is there some design work i can do to avoid turning it into that?

hardy plaza
#

Don't own cats.

amber fulcrum
#

also good shout on guessing i have cats--

#

adklsaklfds

hardy plaza
#

All of my computers are full of cat hair.

amber fulcrum
#

so its less of a design thing and more of a

#

prepare to feather dust my enclosure

#

thing

hardy plaza
#

I vacuum mine, as a feather duster just lofts the cat hair so it can end up on your dinner.

#

But now we're waay off topic.

#

And it's dinner time, I just reminded myself.

amber fulcrum
#

hey it's good tips for care of my pi! it's breakfast time here so im gonna go grab some food myselff

last bramble
#

im gonna use a heatsink on the pi zero and maybe cut some holes for ventilation

fierce spire
#

Where do Variables get saved while the program is running? So is there a limit on how long for example a simple list can be. (I want to first save collected sensor-data in a list because I think it is too fast for my pi zero to directly write them into a text file) Thanks a lot!

hardy plaza
# fierce spire Where do Variables get saved while the program is running? So is there a limit o...

You don't mention which programming language you're using, but generally speaking variables are held in memory. If, for example, you're using Python you can get the free memory using the psutil library, as in:

>>> import psutil
>>> psutil.virtual_memory()
svmem(total=16717422592, available=5376126976, percent=67.8, used=10359984128, free=1831890944, active=7191916544, inactive=2325667840, buffers=525037568, cached=4000509952, shared=626225152)

This will let you know if you're using up too much.

dry galleon
#

So ive just installed NodeRed and Mosquitto on my raspberry pi. Ive subscribet to home/test on my pi but when i send something to it via the MQTT node in NodeRed nothing happens and the node says its connecting.

unknown.png unknown.png
faint sparrow
agile wigeon
#

is a 3.7v 2200mAh battery enough to power a raspberry pi 0 with a display for a decent amount of time?

civic rune
#

Hmm, I think a pi needs 5V? I'm not 100% though

#

Yeah the battery packs I'm seeing are 5V

agile wigeon
#

oh

amber fulcrum
#

also 2200mAH isn't a lot, i did some shoddy maths and i think?? you'd probably get 1-2 hours depending on what the Pi is doing

#

nevermind the display

#

im using a 20,000mAH battery with my Pi + Display

agile wigeon
amber fulcrum
#

Can't really say yet, numbers get a fair bit bigger and im not sure im as confident doing the math for it

hardy plaza
#

...though it's important also to note that a battery used as a charger still charges until it goes below its minimum voltage and (hopefully) shuts itself off. LiPo batteries should not be permitted to run to zero. But the lower limit on a Pi is about 4.75 volts, so the Pi will shut down (reset but not recover) when the battery voltage goes below that level. That may be well before the value indicated by the rated capacity. There are usage curves for batteries and you'd have to see the curve of the battery to see at what point it goes below 4.75 volts to know how much actual running time you have. If the manufacturer doesn't publish a curve then you get to guess.

#

So when I said a Pi that uses 2A would run on a 2Ah battery for an hour, I was lying. 😋

amber fulcrum
#

Alright, good to know, thank you! Most of my maths was okay but I forgot battery voltage dipped 😅

#

If I’m using a power bank and not a straight LiPo, it’ll probably have circuitry to keep the voltage at 5v right?

hardy plaza
# amber fulcrum If I’m using a power bank and not a straight LiPo, it’ll probably have circuitry...

It may have circuitry to keep the voltage from being above 5v, but of course once the battery dips below a certain level it won't supply 5v. It's also important to note that not all power banks actually supply 5v, some (designed as chargers) may supply more than a Pi can handle. See the section "Overpowering Your Pi" on:
https://www.twilio.com/blog/3-ways-brick-raspberry-pi

Twilio Blog
Three Easy Ways To Brick A Raspberry Pi

Does your desk need another paperweight? Learn three easy ways to ruin your Raspberry Pi forever.

#

The power brick linked from the article is listed as a "fast charger" and produces 7v.

amber fulcrum
#

ooof okay

hardy plaza
#

Most USB power banks will tell you what the output voltage is, at least mainstream brand ones.

Probably the best way to find out how long a specific Pi-plus-peripherals will last on a given battery is to write a quick Python program that writes to the system log:

syslog. syslog('message')

and then start that program from a full charge and then it run until the Pi powers off. Then look at the system log to see when it actually did stop logging.

amber fulcrum
#

okay it does say it outputs at 5v,

#

ooh!

#

thats a good idea, thank you

fickle spoke
#

hey so I just got a POE+ hat for my pi4 and when i plug it in, there's a screeching noise, followed by the ACT led turning off. do I have a defective hat?

fickle spoke
#

nevermind, it's working now.

grave condor
#

hello there, first time here. when I connect my raspberry pi pico to my computer, it never runs the script i wrote on it in the beginning. it always opens up the CIRCUITPYTHON folder. how do i fix it?

civic rune
grave condor
#

thank you

civic rune
#

np

pliant pebble
#

Can I take screenshots on a pi with no desktop??

hardy plaza
#

No desktop, no screenshots. If you want a screenshot of a console session you'd need to open a terminal window in a desktop session and do a screenshot of the window.

olive haven
hardy plaza
turbid rivet
faint sparrow
pliant pebble
pliant pebble
#

I have command-line only

pliant pebble
pliant pebble
faint sparrow
#

I built a RPi3 based ebook reader for my mother; it had no window manager so she couldn't easily misoperate it. ;)

#

It just launched FBReader with no window decorations.

#

Ctrl + Alt + Fn still worked but she didn't know about that. ;)

#

(so I could gain access for maintenance)

#

I ended up sitting next to her with a second (Infrared) remote control (which presents as a USB keyboard to the host PC).

#

She'd hit the spacebar on the wireless keyboard I setup for her, when she wanted to turn the page.

#

I'd turn back a page or two after she did so (unbeknownst to her) .. because she didn't learn the timing on the space bar and held it down too long, enagaging keyboard auto-repeat.

#

Raspberry Pi Foundation usually will not supply a person to sit next to you.

pliant pebble
#

haha

faint sparrow
#

my rpi to mcp wiring includes:
RPI - MCP

3.3V - VRef
GND - AGND
SCLK - CLK
MISO - DOUT
MOSI - DIN
CE0 - CS
GND - DGND```
#

and im using the raspberry pi 4b

faint sparrow
#

like the external source, not the board?

steady rose
#

if the other channels are not connected to anything, then they can read noise

#

and just fyi - the library you linked is deprecated, readme has link to current one

faint sparrow
#

oh lol thanks

#

i noticed that earlier but for some reason i thought i migrated to the new code? im kinda dumb lol

faint sparrow
honest maple
#

Hey folks.
I am working on a project I want to make portable and I have some experience with circuitry but I have never made a PCB for instance. I wonder if someone could point me in the right direction to answer a few questions and plan this build.

TLDR I need an AC power supply to a power + charging circuit to run a Pi + accessories

  • I have a list of parts and USB accessories, but I don't know the power consumption of most of these. How can I measure the power consumption of the USB wifi card for instance, to better plan my needed battery capacity?
  • I will need a battery source, I am assuming 18650's and a charging circuit that would allow me to charge + work directly off power.
  • I am afraid of what I do not know here, so while I am looking at different charging IC's if anyone has any input on charging + direct power I would appreciate it.
  • What safety features do I need to consider and where can I find more of this info?
    Lastly, I need to power several separate devices, so this circuit must provide at least four but ideal 5-6 powered USB ports. See #1, I am not sure of the total amperage yet.
  • It would be nice to physically switch on and off USB ports to save power.

There is a 60W 6-Port USB charging hub on Amazon for $20, using AC power of course. If maybe a charging circuit could be added to it that would be amazing but I imagine maybe difficult if the transformer isn't separate.

There may be some slightly easier ways to do this if I assume charging via USB-C

mint leaf
#

I borrowed the oscilloscope, and after some YouTube tutorials, I got everything up and running. With this tool, I found the “problem,” but not the “cause”. Now I am very stumped. So here is the deal. As a refresh, I am working with a Raspberry Pi 4B. I am trying to use PWM from pin 19. Originally, I launched into what I was trying to run and whatnot, but by using the scope, I found my problem is in the PWM signal itself. HERE IS WHAT I AM SEEING: the PWM signal will be at my set percentage (in my example, a 75% duty cycle). For the entire time the PWM signal is being generated, the signal is doing one of two things: 1) staying at the duty cycle I set it at, or 2) switching quickly between two different duty cycles (or a small range of duty cycles), generating the anomaly in my system. To give further explanation, I will post pictures of the O-scope reading.

#

This video is of the change taking place. It is operating at my set duty cycle, then switches to the “quickly changing duty cycles” thing that I don’t want.

#

This picture is a snapshot of the upper side of the “random switching duty cycle” with measurements.

#

This picture is the lower side, with measurements.

#

This picture is just a screenshot of the anomaly, in case the video doesn’t provide enough information. It is switching so fast, that when the scope is constantly measuring, it appears as many lines on the upper side.

IMG_4600.jpg
#

I have observed this unstable signal on multiple (two) Raspberry Pi’s (both 4B). This happens on a raw 3.3V signal AND a stepped up 5V signal. What is observed on the scope is the 5V signal. I only mention this because stepping up the signal was our first try at fixing the problem.

#

For informational purposes, here is the actual project itself, just so you see what I am working on. I call it the King of Kings TechBed: a bed frame of natural wooden appearance that integrates modern technologies, including Adafruit RBGW neopixel lights, Vision Home Theatre surround sound system, relay controlled lamps, relay controlled tri-tiered wireless chargers (smartphone, wireless earbuds, Apple Watch), headboard cooling fans in the headboard, and a mini fridge. I’m an electro-mechanical engineer, and this was my senior project. The issues with the PWM signal for the fans is the last problem I need to solve.

IMG_4601.jpg
hardy plaza
# mint leaf This picture is just a screenshot of the anomaly, in case the video doesn’t prov...

Well, I can't fault you for providing a lack of information but I don't really have any insights into the cause either, except to say that you're doing your PWM from a Raspberry Pi, which is a Linux time-sharing computer. I can't off the top of my head remember if the PWM is using a hardware or software clock, or whether it's affected by system load. And if and how you're running your program in Python whether that might affect PWM if it's not a hardware PWM.

So the only way I can suggest searching for that cause is to isolate the problem, perhaps by trying to run the PWM on a dedicated MCU to see if it's Pi-related or not, or somehow more hardware-specific.

midnight sage
#

I'm gonna work on a BMC64 soon and I would love to simulate that Datasette port to the Pi 3 B+ what pins of the GIPO I need to connect to make the actual datasette talk to the Pi?

last bramble
#

trying to do a headless raspberry pi setup

#

i cant seem to ping or ssh into my pi

#

and all its showing is a red light

#

so im not sure whats happening here

olive haven
#

@last bramble Which Pi? How are you connecting -- wifi? I've found using Imager is the best & easiest way to get wifi & ssh set up.

last bramble
#

i connected the wifi through the pi imager

#

and for some reason it wont pick up my pi's hostname when i ping it

#

sorry for late response btw

olive haven
#

You're trying to ping whatever.local?

last bramble
#

nope

#

just the name

olive haven
#

Try it with .local

last bramble
#

or do it now?

#

and when i do ping, i get the usual "name or service not known" error

olive haven
#

I usually wait till the disk activity light calms down a bit, then try it

last bramble
olive haven
#

What kind of computer are you pinging from?

last bramble
#

im on a linux machine

#

nixos to be specific

olive haven
#

I don't have a 4 so I don't know what color lights it has.

last bramble
#

and i still get the "name or service not known" error

olive haven
#

The .local thing is ZeroConfig (or Bonjour, though I think just Apple calls it that.) You should see if that's a service that's enabled or that you can enable.

#

(I've never configured it on a Linux, so can't help with the specifics.)

last bramble
#

my only option is to wait for my microhdmi adapter to arrive so i can find out whats actually going on

olive haven
#

The only glitch like this that i've run into is when I configured wifi to try to connect to the 5G band of my router rather than the 2.4G -- the 3 and Zero at least only like 2.4

last bramble
#

i think ill just wait for my micro hdmi adapter to arrive rather than doing a headless setup now

olive haven
#

(I've been trying to get a 4, but that's kinda hardthese days)

last bramble
#

it took ages to find one

#

for me

faint sparrow
#

Not at all. Just gotta be able to pay $7000.00! <laugh>

olive haven
#

I got mail from Adafruit that they were back in stock, but didn't see the mail until an hour later -- all gone.

faint sparrow
#

I really wish they'd do a "pre-order" rather than a email list. Be nice to put the money in and be queued to get one.

last bramble
#

i got mine from a nearby store

olive haven
#

yeah, that'd be nice. (For $7K I'd get 2-3 Macbook Pros...)

#

The local MicroCenter had them for a few hours last weekend, but I missed out on that.

faint sparrow
#

I really wish we could get chips up to full speed and get back to normal.

olive haven
#

Yep. I've seen a few estimates like "maybe in 2023"

#

The pandemic just shut down Shenzhen.

wraith grove
#

on linux if you're sure the pi is on the network you can
nmap 192.168.1.* -p22 # adjusting the IP numbers to match your network
and find just about everything on the network with an ssh port

#

they will be marked as open if it has ssh running

last bramble
#

i switched to my windows install to see if anything worked

#

used angryipscanner

#

and still wont pick up my raspberry pi

#

for whatever reason

last bramble
#

nevermind, found out what the issue is

olive haven
last bramble
#

so it took me a bit to find the raspberry pi's ip address

#

then used that instead of the hostname

silk tapir
#

My 3 died, keeps undervolting on the stock power supply, and I can't find rpis anywhere

#

Even another 3 would be fine at this point

#

But I would like a 4

civic rune
#

Yeah it's rough these days.

#

Rpilocator might help

fickle shale
#

Today I found that a fresh install of Raspberry pi OS lite comes with python 3 and python 2.

#

Is there a way to make python 2 default?

civic rune
#

Just curious, why would you want to?

fickle shale
#

old tutorial

civic rune
#

Ahh

fickle shale
#

I tried it with python 3 but it made errors

#

Maybe there's a way to call python 2 instead of python 3 in the command line

woven cargo
#

I am trying to display a count value in a loop on a raspberry pi zero. It works but when it displays multiple lines of it updating the count value, the pi lags significantly. Is there a way to code it to where is will just update a single line versus printing a new line everytime. It is counting the number of steps a stepper motor has taken. Thanks in advance. I'm a newbie here.

silk tapir
#

Is a cm usable?

civic rune
#

I'm not super familiar with it

silk tapir
#

It has a ribbon cable io

#

I don't think it's useable

#

@civic rune is there anything that is the price of a pi that will work for hosting a discord bot?

#

Like a mini PC or something

civic rune
#

I'm sure there are, there are lots of other SBCs out there

fickle shale
#

Ah, I found that the python version is not the problem. On to other problems 🙂

silk tapir
silk tapir
#

Also just use python2 in terminal

#

Instead of python

fickle shale
civic rune
#

I don't know if it's legit or which alternatives are good, you'd have to compare and contrast specs and look at reviews. I only have experience with the pi

silk tapir
#

Well it is a pi4 supposedly

civic rune
#

I avoid amazon for electronics tbh but ymmv

#

Well for hot commodity electronics

silk tapir
#

My dad won't do anything other than Amazon unless I do a whole bunch of research

civic rune
#

Huh

#

Well, there are alternatives for many products. I haven't bought a SBC on digikey but that's where I get 90+% of my project parts for example. I'd never buy an IC on amazon.

silk tapir
#

Ok

#

Digi key arrival estimate is 2023 😨

civic rune
#

Yeah

#

Chip shortage is only going to get worse

silk tapir
#

Can I get like a 3b or 3b+?

civic rune
#

I use those for my work but I don't know if they are up to hosting a discord server. In my experience they struggle a great deal to browse the web

silk tapir
#

A 3b is what I have now, and it works

#

Cpu idles at around 20-30%

civic rune
#

If it's available go for it

silk tapir
#

The 3b+ are 185 🤦‍♂️

#

I might suck it up and try to fix mine

olive haven
#

For the time being, they're only making the 4's and the Zero W 2's.

silk tapir
#

Yeah I dont think a zero will work

olive haven
#

The brownouts might just be a problem with the micro USB connector, maybe even just an accumulation of dust in it. You could try cleaning it out with compressed air.

#

Or you might be able to power it through the pins.

devout needle
#

I ran a code and it said that I needed python 3.7 so I downloaded python 3.9 but it's still saying that I have python 3.4 version is there any way that I can change this? I'm new at pi so any help would be greatly appreciated

hardy plaza
# devout needle I ran a code and it said that I needed python 3.7 so I downloaded python 3.9 but...

Probably the easiest way to upgrade you Python version is to back up any files you have on your Pi and just download a more recent Raspberry Pi OS and install it on an SD card. I believe the Python on the lastest OS is version 3.9. If you're using a Pi desktop messing about with version of Python can potentially make the desktop inoperable, i.e., if you do it wrong. If that's not an issue and you want to upgrade Python the most reliable way of doing it is to compile and install Python from the make tool. I've written up a wiki page on upgrading Python this way: https://service.robots.org.nz/wiki/Wiki.jsp?page=UpgradingPython

#

But compiling your own Python, while an educational experience, isn't really necessary and takes a fair amount of time (on a Pi Zero, hours). The easiest way on a Pi is just install a new OS on an SD card.

hardy plaza
#

I'm setting up some web services on my local (home) network (just for use in my house) and was wondering if using a spare Pi 4 as a DNS server would impact on performance of the rest of the computers on my network, i.e., if interjecting my own Pi 4 based DNS server would slow down name resolution enough that I'd notice it. I also have a spare Jetson Xavier I could use but that'd be more complicated to set up. Don't know if the difference between the Pi 4 and Xavier would be appreciable.

Also, I've found a few web pages on how to set up a local DNS but if anyone has a really good reference on how to do that it'd be much appreciated.

spice kayak
# hardy plaza I'm setting up some web services on my local (home) network (just for use in my ...

I think it would be a speed increase to run your own caching resolver versus relying only on the upstream or the outside (8.8.4.4). If your router was your resolver, the switch may not be noticeable. Still, it is good to setup because you may be interested in doing a sinkhole config like the pi-hole project which is in an Adafruit learn guide. I did something recently by following the Openbsd pf guide, but it was to run the pc in place of the router because it died/ no longer reliable.

hardy plaza
spice kayak
hardy plaza
#

Thanks, may have a go at that.

stray robin
#

Hello there! Have anyone used Electret Microphone Amplifier - MAX9814 with mcp3008 and raspberrypi and have succeded? I am trying to record using this type of microphone. Thank you very much!

unborn rapids
#

Is it possible to connect a Monochromes 1.3 with the raspberry pi pico?

tired marsh
#

you pick valid I2C pins, you connect those and the power pins, and you're good to go

unborn rapids
unborn rapids
tired marsh
#

just make sure to check the address of the screen

unborn rapids
turbid rivet
#

For the Pi Pico, you can pick any valid pair of I2C pins, as long as you define the pins accordingly in software. https://pico.pinout.xyz/ labels the I2C pins in blue, so take your pick.

Raspberry Pi Pico GPIO Pinout

An interactive, accessible and beautiful GPIO Pinout guide for the Raspberry Pi Pico

unborn rapids
#

Ok thanks, really helpful

tired marsh
#

SDA is Data and SCL is Clk on the screen's pins

unborn rapids
#

I connected scl pin 2 with clk (on the display)

#

the code: >>>
from machine import Pin, I2C

i2c = I2C(0, scl=Pin(2), sda=Pin(1), freq= 200000)
print("I2C Address :" +hex(i2c.scan()[0]).upper())

ruby night
#

The name of the pin id GP1

#

use i2c = I2C(0, scl=Pin(1), sda=Pin(0), freq= 200000)

#

also it does not look like the header pins are soldered to your display -- it won't work if they are not soldered.

unborn rapids
#

Traceback (most recent call last):
File "<stdin>", line 6, in <module>
IndexError: list index out of range

#

the code :

i2c = I2C(0, scl=Pin(1), sda=Pin(0), freq= 200000)

print("I2C Address :" +hex(i2c.scan()[0]).upper())

tired marsh
#

it's not soldered to the pico either it looks like

#

better: print([hex(addr) for addr in i2c.scan()])
but it will be empty, hence the error

unborn rapids
#

it doesn't have to be soldered? i'll do it on a breadboard

tired marsh
#

the pins have to be soldered to the board

#

then shoved in the breadboard

unborn rapids
#

output : []

tired marsh
#

there's no contact if it's not soldered, just loose wires barely touching when you sneeze

unborn rapids
#

ok wait a second !

unborn rapids
#

Next try

297DD4F4-25A7-4DB1-9260-64797EE3C8DB.jpg
#

The output is []

#

lol

#

Is this good ?

umbral sable
#

It just means no I2C devices were detected on the bus. Whether it's good or bad depends on whether you expected something to be there.

unborn rapids
unborn rapids
unborn rapids
turbid rivet
# unborn rapids

SSD1306 looks for a device at address 0x3C, but no such device exists.

#

Not sure what 0x08 corresponds to, but it certainly doesn't seem like an SSD1306.

#

Where did you get your display module from?

unborn rapids
turbid rivet
#

Hm, should be right. Why is it getting an address at 0x8...

unborn rapids
#

I don’t no 😦

#

Should I use other pins ?

#

For scl and sda

steady rose
#

did 0x08 actually show up in an I2C scan?

unborn rapids
#

0x8

steady rose
#

what scanner program is that?

unborn rapids
#

Thonny

steady rose
#

does Thonny have a built in scanner?

unborn rapids
#

No I scan with py

steady rose
#

what is the scanner program being run?

unborn rapids
#

That’s a script

unborn rapids
steady rose
#

looks like you're running micropython on the pico?

unborn rapids
#

Yes

#

And I wanne get output on the Monochromes OLED Display

steady rose
#

try freq=100000

#

in the I2C setup

unborn rapids
#

Thanks, I will try it tomorrow

steady rose
# 
from machine import Pin, I2C

i2c = I2C(0, scl=Pin(1), sda=Pin(0), freq=100000)

print("Configuration:")
print(str(i2c))

print("Scan results:")
print(i2c.scan())
#

can also try that as a simpler scanner

#

verify you can get 0x3c

pliant pebble
#

Mu as the editor???

opaque wagon
#

? The editor in the photo looks a lot like Mu but the tabs aren't that square in Mu

unknown.png
unborn rapids
unborn rapids
civic rune
heady cedar
#

I don't usually use the Raspberry Pi desktop, but noticed this low-power message today. I have my Pi plugged in via the USB port on my MacBook Air. Is it OK to do this? I've noticed some students have been having a problem with their Raspberry Pis & wonder if this could be a problem. Is there an easy solution, side from buying the Pi power supply? For example, I've run Pis off of an old mobile phone (usually iPhone) power supply - plugging USB directly into that. Is this also an acceptable solution? Thanks!

unknown.png
turbid rivet
heady cedar
#

Pi 3 A+

turbid rivet
#

A 2.1A wall charger would be the best you could do without a specialized supply, but it should minimize throttling on your Pi if those are the options.

#

I know 3 B+ called for 2.5A, have to look up 3 A+...

#

Well @heady cedar, it should be fine if you run it off the wall. Looks like under load, a 3A+ would consume ~4.1W, so if you can supply even an amp, you should be able to run mostly without throttle. I wouldn't recommend the USB port on the PC, as those typically only deliver up to 500mA, and some PCs will even shut the port off if you try to draw more....

heady cedar
#

Thanks so much! This is very useful. I've had my students plug into their PC & use Ethernet to get the MAC address, which is needed to register the Pi for headless use on campus. Once they get that & get WiFi setup, then I suspect some of the problems some have experienced might go away if they run their Pi off a separate mobile phone charger. I appreciate your advice. As always - feel free to correct me if I've got this wrong. Cheers!

turbid rivet
#

No problem! If they run into issues during setup, you may have to recommend that they power the Pi off the wall then, too. Generally speaking, though, if the port isn't cutting power to the Pi and you're not running off the port for extended periods of time, you should be okay for an initial setup. I'd be careful running off the USB ports for extended periods of time, as high power draw is more a risk to the PC than it is to the Pi...

heady cedar
#

Thanks so much. I've had weird issues where students who had been able to connect to WiFi suddenly had the connection drop. I'm hoping that it's just that these students were powering off the laptops & that a switch to a mobile phone USB charger will help. Very kind of you to reply with such helpful guidance. Cheers!

steady rose
#

@unborn rapids check wiring. not sure if micropython does the pull up resistor check that circuitpython does.

#

@heady cedar yep. agree that network behavior is likely power related. that power warning on the pi is pretty sensitive. you can get away with powering via USB for a while. to like SSH in and check some things out. but for reliable behavior, a good power supply is needed. which won't be a USB port.

pliant pebble
pliant pebble
wintry apex
#

Hi All - I'd like to send a UART command from my Raspberry Pi to my uC board (8-bit AVR Arduino compatible) such that it will have the same formatting as it does when being sent from the Arduino IDE Serial Monitor with the "No line ending" option selected.

Is there anything special I need to do with the PySerial write() command to make that happen?

The command is a 3 or 4 character number, and we're reading it on the microcontroller side with Serial.parseInt().

umbral sable
wintry apex
#

I'll keep at it.

umbral sable
wintry apex
#

I just realized I was forgetting to do the byte conversion.

#

...in my Python code.

#

Thanks for the quick help! Jogged my memory.

turbid rivet
wintry apex
#

Indeed. I ended up going back to basics with some simple type(x) commands in the REPL to get my head around what was going on. 🙂

#

Now to add some eye candy to my terminal app with Textual.

hardy plaza
# heady cedar Thanks so much. I've had weird issues where students who had been able to connec...

I'd say a sizeable majority of problems people have with Raspberry Pis are related to power supply. It's almost unfortunate that it can be powered by USB since that gives people the impression that plugging a Pi (often including additional peripherals) into a USB port, a USB power bank, etc. should just work. The Pi actually is meant to run at 5.1 volts, not 5.0 volts, and will stop operating and reset itself around 4.85v. So at 5 volts the Pi is already working under its optimal voltage, and not all USB power sources even provide 5 volts (some lower, some dangerously higher — fast chargers at 7 volts will immediately smoke test your Pi). Power supply voltages typically brown out (drop) under load, so pushing the power supply with a display, WiFi, a fan, etc. often leads to problems.

In terms of choosing a power supply it's good to overspecify by maybe 20% as you'll want a buffer. E.g., a bare Pi 4 B requires 3 amps (15 watts), a bare Pi 3 B+ 2.5A Overclocking would increase the requirement. Additional peripherals would also add to that value. You'll sometimes see "idle" power specified but that's rather useless for specifying power supplies unless your Pi will never do more than idle.

turbid rivet
#

Thankfully, Pi 3A+ is slightly lower in power consumption, and 7 volt fast chargers aren't all that common yet...

civic rune
#

Don't those only provide 7Volts if the pullup resistors on the device under charge are right?

#

otherwise they provide 5?

turbid rivet
#

They should negotiate with the device via the CC resistors, but it's best not to assume all devices are built to spec. Who knows what kind of cheapo threw together a "fast" charger without thinking about that...

civic rune
#

that's very fair

unique totem
#

I've had some issues initially setting up my raspberry pi over my school's wifi network. I've followed all the necessary sets exactly as students who have theirs working have but I keep getting the error (ssh: Could not resolve hostname mbarnes: nodename nor servname provided, or not known).

#

I am about to login over ethernet, but not when over wifi

#

able*

#

If anyone has any suggestions I would greatly appreciate it

hardy plaza
civic rune
#

I definitely wouldn't use a charger that I can't verify the performance of, I agree.

#

Official or very very highly regarded 3rd party only for me

stray robin
#

Hello! Could anyone obtain more than 1000 samples /second with mcp3008 and rpi4?

rotund pivot
#

what is the SPI frequency?

devout needle
#

So I downloaded python 3.8.0 and tried to install matplotlib on my pi but I keep getting this error, how do I resolve it?

IMG_3815.jpg
stray robin
hardy plaza
hardy plaza
rotund pivot
#

@stray robin Might help to share your code and setup, so we can see what libraries are being used (blinka vs spidev have different ways to set frequency). The datasheet https://cdn-shop.adafruit.com/datasheets/MCP3008.pdf specs the sampling rate much higher, but the bottleneck is more likely to be Python.

devout needle
vague bear
#

Hi all,
I've got a very poorly supported physical add on device that allows me to open my garage door (hooks to the same terminals that the wall button does).

I would love to get a raspberry pi to do this as I'd feel more in control (plus I could set up an endpoint that would be reliable to accept the "button push")

However, does anyone know how I would wire this? (Thanks in advance)

stray robin
# rotund pivot <@!249810340819369994> Might help to share your code and setup, so we can see wh...

This is the code using adafruit library:
import Adafruit_MCP3008
import Adafruit_GPIO.SPI as SPI
import busio
import digitalio
import board
import adafruit_mcp3xxx.mcp3008 as MCP
from adafruit_mcp3xxx.analog_in import AnalogIn
spi = busio.SPI(clock = board.SCK, MISO=board.MISO, MOSI=board.MOSI)
cs = digitalio.DigitalInOut(board.D5)
mcp = MCP.MCP3008(spi,cs)
es = []
def myadc():
channel = AnalogIn(mcp, MCP.P0)
es.append(channel.value)
ok = 1
k = 0
try:
while ok:
myadc()
except KeyboardInterrupt:
ok = 0
But i can obtain only 1000 samples/sec

Using spidev:
import time
import sys
import Adafruit_MCP3008
import Adafruit_GPIO.SPI as SPI
import spidev
spi = spidev.SpiDev()
spi.open(0,0)
spi.max_speed_hz = 3600000
mcp = Adafruit_MCP3008.MCP3008(spi=SPI.SpiDev(0, 0,3600000 ))
ok = 1
try:
while ok:
es = mcp.read_adc(0)
arr.append(es)
except KeyboardInterrupt:
ok = 0
But using that i got the following error :
Traceback (most recent call last):
File "/home/pi/Desktop/de3.py", line 9, in <module>
mcp = Adafruit_MCP3008.MCP3008(spi=SPI.SpiDev(0, 0, 50000))
File "/usr/local/lib/python3.7/dist-packages/Adafruit_GPIO-1.0.4-py3.7.egg/Adafruit_GPIO/SPI.py", line 46, in init
self._device.cshigh = False
SystemError: error return without exception set

civic rune
vague bear
civic rune
#

Ohhh you want web based

#

I misread

#

And esp based board could also work? Pi boards are just hard to find right now is my main concern

vague bear
#

I've got one already that I've dogeared for this project.

civic rune
#

Ahhhhh

vague bear
#

It's currently only running a little wordpress instance. 😂

civic rune
#

Carry on! I was just trying to help you avoid a headache if you were without a board

rotund pivot
#

@stray robin I don't know about the spidev exception, but I don't think you need to set the frequency that high, the MCP3008 runs lower... check the datasheet. In the first case, you are initializing the AnalogIn in every loop, try doing that just once at set-up time, and simply do the read within the loop.

stray robin
#

is that possible with some instructions or should i modify the code in order to run faster

rotund pivot
#

I'd fix the init first and see where you're at, the default may be good enough. The libraries typically set the frequency but iirc when I checked MCP3008, it doesn't change the default, but you can find frequency-changing SPI code in other Adafruit CircuitPython SPI device libraries

#

the list [] of results is going to grow quite large, and quickly

#

I'm pretty sure that changing the SPI bus frequency in code.py will not help... each SPI device locks the bus when it's using it, and can use its own frequency

#

so you'd need to mimic that, may need to alter the library

stray robin
#

Thank you very much for your support.

stray robin
# rotund pivot I'd fix the init first and see where you're at, the default may be good enough. ...

I have tried this code using another library and changing CS from GPIO6 to GPIO8 (chip enable SPI0):
import time
import spidev
from gpiozero import MCP3008

ok = 1
adc = MCP3008(channel = 0,clock_pin = 11, mosi_pin = 10, miso_pin = 9, select_pin = 8)
es = []
a = time.time() + 1
while time.time() < a:
es.append(adc.value)
print(len(es))

I could obtain 6000 samples / s , but the problem is that i obtain only the same value for all my samples = 0.00004885.
When i change GPIO8 to GPIO6, i get again only 1000 samples/s and the samples are correct

rotund pivot
#

I'm not familiar at this depth, maybe someone else has experience with the MCP3008

#

what happened in the first case above when initializing channel only once?

stray robin
#

maybe rpi is not fast enough, i really don`t know

rotund pivot
#

well, the first example does use default SPI speed, I don't know offhand what that is

stray robin
#

my propose is to get the samples from a max9814 microphone ( analogic one)

#

maybe is there another method to do that? another ADC or a rpi boost hardware

rotund pivot
# 
>>> 5/1024
0.0048828125
```what range of ADC values were you expecting in your test?
stray robin
#

25000, like that

rotund pivot
#

it's just a suspicious number you got repeatedly... it's roughly the 10-bit granularity ...in the 3rd case

stray robin
#

this is an imagine with 1000 samples/s

3xKrG.jpg
#

maybe i get only the adc noise

#

cuz he don`t see anything as an input

stray robin
rotund pivot
#

you mentioned powering the MCP3008 at 5V, but if I'm not mistaken, the GPIO signals are at 3.3V ...is the MCP3008 verified to function this way?

stray robin
#

i read in datasheet about powering mcp3008 at 5V is boosting his ksps to 200

#

but only 75ksps if it is powered at 3.3V

#

anyway no one of these 200ksps or 75ksps is reachable

rotund pivot
#

I'd maybe try VDD and VREF at 3.3v to rule out some oddity there, it should still be capable of >75ksps (but the bottleneck will likely be upstream)

#

right, this sounds like audio (pun intended), but you're not going to get to 44.1 with this setup

stray robin
#

i wanna obtain 8khz

#

not great, not terrible

rotund pivot
#

default SPI with Blinka may be only 100kHz, not sure offhand how / if that can be changed without modifying the library

stray robin
#

all i found referes to micropython

rotund pivot
obtuse merlin
#

I have a very weird concept in my mind.

I would like to connect two RPI‘s physically (not via wifi) and use one for, lets say, coding and another one for compiling and backups of code. Can I write a script that sends code to the other Pi, compiles it, checks for errors and:

  • If a error occured, let the Main Pi know

  • If the Compile was succesful, create a backup of the src and push to a git repo aswell as let the rpi know.

? Its a crazy idea but I have two pis and would like them to work together. This is an idea i haf

umbral sable
turbid rivet
obtuse merlin
turbid rivet
#

Might not be ideal for larger Pis, but in that case you could also use a standard UART connection from Pi to Pi.

#

It provides power and a serial port over USB, which is perfect for a Pi Zero, but may draw too much power if you plan to use a 3B or 4.

#

Though if you're using a Pi to talk to the Pi, you could just wire the UARTs together and create a serial connection that way.

obtuse merlin
#

Ahh okay well I was originally thinking of using two 3Bs

#

Im pretty new to serial connections. Can I use SSH via this connection then?

turbid rivet
#

You could SSH to one Pi, which would simply communicate directly over Serial to the other?

#

SSH is pretty much just the secured network equivalent of a serial connection, anyhow.

umbral sable
#

(Sorry, I mentioned ssh because I missed that you weren't using WiFi. You wouldn't need it for just a direct serial connection.)

obtuse merlin
#

Okay well in other words i can use the terminal of the other pi via serial?

turbid rivet
#

Yes, absolutely.

obtuse merlin
#

Ahh okay. Hey that might be perfect actually

turbid rivet
#

You wouldn't even need the PiUART if you're using two Pis, just wire Tx on one Pi to Rx on the other, and vice-versa.

#

The only other thing would be to configure both serial ports to run at the same baud rate.

obtuse merlin
#

I have a completely headless Pi (no ports etc. just power and hdmi for troubleshooting). Which i plan to put in a enclosure with another headless pi. One as a main remote machine for coding for fun, and the other for other stuff like compiling.

#

Also, is there a way i can power a rpi from another rpi? Or should I use a rpi zero for that

turbid rivet
#

Theoretically, you could wire the 5V and GND pins on the GPIO together to share power, but you would need to make sure you have a high enough current rating on your supply to sufficiently power two Pis. A Pi Zero would be significantly easier to power from another Pi, due to its lower current draw, but you still have to perform the same checks.

obtuse merlin
#

Now im thinking of just using a rpi 3b and pi zero (the zero for compiling). Would it be possible to power them both via one usb 3 port?

turbid rivet
#

You could probably get it to work, but if you load the Pi 3B with enough work, your port's overcurrent protection could cut power abruptly.

carmine hollow
#

I think I just murdered my Pi Zero W... Anyone have any articles on how to troubleshoot a possibly dead board? I've already checked the power rails and power is getting places, but the activity LED is not lit ever.

olive haven
#

That's a lot easier to replace than a Pi these days!

carmine hollow
#

in a panic I bought a pi4 2gb... apparently the last one adafruit had

#

I can still use it, but now I feel bad that I took the last one

civic rune
#

shakes fist

#

Jk, congrats

turbid rivet
carmine hollow
#

yup, I think I'm going to try and turn it into a DOSBOX-X machine with a Sudomaker Retrowave OPL3 HAT

#

which, by the by, is REALLY poorly documented

wanton holly
#

is there a OS version for a RP3B+ that has OpenCV precompiled in it?

turbid rivet
lucid crest
#

I was wondering if I could get some help with the Trinkey QT2040. I'm going through the tutorial on this page: https://learn.adafruit.com/adafruit-trinkey-qt2040/blink-2, and I was able to get it to upload once, but it won't upload again. I checked the settings within the Arduino IDE to make sure they're the same, and I tried the manual bootload method mentioned in the tutorial, but nothing seems to be fixing it.

#

Here's the error message I'm getting:

unknown.png
steady rose
#

are you seeing the RPI-RP2 folder when you go into bootloader mode?

#

or...actually...the upload looks OK maybe

#

what is the sketch you're trying to upload?

#

the same blink example from guide page?

lucid crest
#

Yes, I am seeing the RPI-RP2 folder when I go into bootloader mode. It would even pop-up for a split second when the Arduino IDE was trying to program it.

lucid crest
lucid crest
#

If it's any help: I'm able to use the same board with CircuitPython without much problem (I think the issues I'm seeing are with Mu rather than the device itself). Also, I'm seeing this on multiple Trinkey boards.

woven cargo
#

I am trying to constantly read the current time and then if within a certain time range perform an operation. I have got a while loop that will read the time, but I guess I cannot read a variable inside a while loop? Any help would be much apricated.

Capture.PNG
tired marsh
#

first, you have 2 infinite loops, only the first one runs

stray robin
#

hi! Does anyone used mcp3008 and mcp3002? With which of them could you obtain more samples/ sec using blinka?

umbral sable
stray robin
umbral sable
#

I wouldn't expect any differences between chips if Python is the bottleneck.

stray robin
#

So, there is a problem with python

#

Latency of python

umbral sable
#

Hard to say offhand, since it might also be things like the SPI bus clock rate, but it could be, yeah. There's likely a lot of overhead involved in the path from the Python interpreter down to the actual bus transactions.

stray robin
#

I see. Anyway, i was just interested in knowing if someone else could obtain more than 1ksps using blinka and mcp3008 or 3002

#

Just for me to know if it deserves to go on with mcp and pi

rotund pivot
#

i could be wrong, but when I glanced at the library, it defaulted to 100kbps SPI with no way to change at runtime, so it may need a library tweak to see if increasing that helps overall sampling rate

turbid rivet
#

Each sample should be about 3 bytes worth of SPI transaction, so 100kbps should be able to deliver upwards of 30ksps on a dedicated SPI bus? I would assume the Python overhead would be a more significant source of delay, but I'd have to see the code to determine that. If you use some time benchmarks, you might be able to see how long one sampling code block takes to run...?

umbral sable
turbid rivet
#

Oh, kbps is kilobits... Right.

#

Okay, yeah, so 100kbps is only like 4k transactions per second. Whoops.

rotund pivot
#

The bulk of the time could well be in the library, but 4K theoretical vs. 1K actual is a pretty close margin and I think @stray robin is running on a Pi 4. Python on even a Zero will loop IO operations pretty fast. It may be worth trying to boost the SPI speed (or instrumenting the library).

hardy plaza
# rotund pivot The bulk of the time could well be in the library, but 4K theoretical vs. 1K act...

If you're really going for performance you could write the code in C and provide the hooks to call it from Python, see: https://realpython.com/python-bindings-overview/

Python Bindings: Calling C or C++ From Python – Real Python

What are Python bindings? Should you use ctypes, CFFI, or a different tool? In this step-by-step tutorial, you'll get an overview of some of the options you can use to call C or C++ code from Python.

midnight sage
#

Who knows how the usb power adapter is wired for the raspberry pi 3b+ models bmc64 used a positive center barrel jack

hardy plaza
midnight sage
hardy plaza
#

...like I'm using a short cable to connect a battery on my robot that was actually purchased from a local guitar shop.

midnight sage
#

Well basically I know GND can be on the sleeve of the barrel jack while if I'm correct 5v goes on the center pin and it should give me the center pin polarity needed for bmc64

hardy plaza
midnight sage
#

Sometimes it needs to be the other way around for most electronic devices too

hardy plaza
# midnight sage Sometimes it needs to be the other way around for most electronic devices too

Well, unfortunately nobody thought to standardise this so there are manufacturers and product domains where it's center negative, which is frankly kinda dumb because that means the metal shell of the barrel is hot (5v) and not ground. Most of the products I deal with (laptops, robots, musical instruments) are center positive. But yes, there are products out there like that.

midnight sage
#

I've checked everywhere for a little housing once I'm done with it, unless I get an old female Micro usb and use it to make a barrel jack cord

to me buying a 5V 2.5A ac is crazy if I can just use what I have to power it with a simple diy converter

hardy plaza
#

...and then I use those aforementioned guitar effects box cables for power connections since they're relatively cheap and locally available at any musical instrument store

midnight sage
#

I'm looking for a 3d printed mount for those breakout boards if I have to route to that for a Female Micro USB to be used

#

it's like a casing to put inside a sparkfun micro usb breakout board inside

midnight sage
hardy plaza
#

Ah, yes, I know what you mean now. I have one of those little breakouts, the male version. Sorry, I can't think of an easy solution. I just mounted mine with a couple of standoffs, but I'm not using an enclosure at all.

midnight sage
#

if I have to get this to make one then I need some sort of casing from PLA

faint sparrow
#

They have the bare connectors iirc - solder them yourself.

hardy plaza
midnight sage
#

Adafruit is delayed in shipping I just basically need a simple board to use as I'm not panel mounting it I'm just making a little usb converter

hardy plaza
#

These aren't actually made by Adafruit, should be available from other vendors.

#

Sorry but I'm still confused. Are you trying to duplicate the SparkFun breakout or already have one and are trying to integrate it?

midnight sage
#

I wish to make a little converter that I use my micro usb Pi 3B+ apdater I already to barrel jack it's for BMC64 I'll be making soon using the Pi 3B+ as a C64

hardy plaza
midnight sage
#

I could use that but no one made a 3d printed casing for it I just need something I can make for a DC Jack

#

just finding which one is better to make

#

I'm taking my Pi's AC and create a female Micro usb to Barrel jack converter for any project that uses one

hardy plaza
# midnight sage

Ah, thanks for the clarification. For that purpose I've ended up using the panel mount ones, as that suits my requirements (e.g., battery connection to a robot).

#

Sorry I couldn't be more help.

midnight sage
#

I might use this for my pi Zero w as that's my dreamcast router

hushed nimbus
#

Hey guys

#

I'm trying to run this Java program on my pi 3, and I want it to be headless

#

I want the program to take input from a USB barcode scanner, which is basically just a keyboard

#

I'm having it use System.in to get the input every \n

#

And sure, that works on my development laptop where I have the program's console right there, but now I don't know how I'd get the program running on my raspberry pi as a background program while getting input from System.in like this

#

Is this possible?

olive haven
hushed nimbus
#

I can type it, or plugging the scanner into my computer also works

#

But it works since I have the program's console right there

#

Now I don't know how I'd get standard input to point to a background program like this

umbral sable
#

It's a little bit of a contradiction. The "foreground" process is the one you're interacting with via the mouse and keyboard. So having a "background" process that is the thing grabbing user input doesn't make much sense.

hushed nimbus
#

Hmmmmm

#

I'd just like to capture what the scanner sends in this program

#

I guess this just wasn't the way to go

#

What do you think I can I do instead? @umbral sable

hardy plaza
# hushed nimbus And sure, that works on my development laptop where I have the program's console...

The "System.in" you're talking about is available from your terminal session. If you're running headless without a keyboard (i.e., you want input from the USB device, not from the console) there is no user terminal/console, so you'll have to read from the USB device directly, not from the console. So you'd no longer be using System.in, you'd have to figure out how to get input directly from the USB device, and put a loop StreamReader (or something similar) onto that.

hushed nimbus
#

I see

hardy plaza
#

You should be able to launch your program from the workstation and run it without interaction from you on the keyboard. You can start that on a Pi using a variety of methods (e.g., systemctl) on the Pi's Linux, but first you need to be reading directly from the USB device.

#

And if you don't already have a USB library, I know of several available but here's one: http://usb4java.org/

hushed nimbus
#

Thanks for the library, I’ll look at that

mint leaf
# hardy plaza Well, I can't fault you for providing a lack of information but I don't really h...

End of the story:
There was no solution that would work for the raspberry Pi. In the end, I pulled the PWM control from the Pi and used an Arduino instead. I figured out a program that would allow setting the HZ based off the internal clock, and control two different PWM fans (at the same frequencies, different duty cycles) that way. There were other benefits, but I don’t want to waste your time going into unnecessary details.
Thank you for all of your help. The oscilloscope was the key. I appreciated your advise and thoughts on the matter. The project is now fully functional, and everything I’ve ever dreamed it would be.

hardy plaza
honest maple
#

I got a CM4 8Gb! But tbh, I want a regular raspberry pi lol. Can anyone recommend a daughter board?

novel vault
#

I've been trying to get my pigrrl zero working with my pi zero 2 w for a while, and was thinking it was mostly just couldn't get the 2.2 PiTFT screen working.

I eventually (just now) wrote the rasbian image, stuck the SD card in a Pi 2b ive got on hand, and followed the pitft instructions from adafruit.

Moved the SD over to the pi zero, and it's got a white line. Does anyone have a good idea for what could cause this? (Image in next message)

#

hmm, maybe this should be in 'help with projects'?

carmine hollow
#

white lines in displays usually aren't software

#

but I could be wrong

novel vault
#

yeah I'll head over to 'help with projects', at least to narrow down where the issue might be.

stray robin
#

hello! did someone interface raspberry with pdm mic?

foggy onyx
#

Its happening even if sd card is removed

wraith grove
foggy onyx
#

When sd card is incerted

#

And it shows nothing on screen in both cases

foggy onyx
wraith grove
#

there have been anecdotes that adding hardware to the pi could make it work for a couple days
getting a new one is the clearest solution, and maybe seeing where your warranty stands

foggy onyx
wraith grove
#

if we've interpreted this correctly, something is wrong with the ram or the connection to the ram, etc, if you're a whiz at remanufacturing BGA chips, perhaps you could fix it?

foggy onyx
#

On inserting sd car it doesn't blink. So, i think i should try a last option

#

Reinstalling OS

woven cargo
#

Is this valid. I can't seem to get this to work.

While GPIO.input(15) == GPIO.LOW
'
ruby night
steady rose
#

W should be w (case) and need a : at end of line

while GPIO.input(15) == GPIO.LOW:
    do_stuff()
#

but also not sure what exactly is happening, so would need more info on what is not working

foggy onyx
#

Rass don't show problem of 8 blinks

#

It just reported no sd card as normal

#

But when i started with sd card inserted

#

The ACT light doesn't light up

#

What should i do ????

#

Then i started with no sd card and i inserted sd card in between

#

I got this

20220330_213801.jpg
#

Someone please help here

#

🙏

olive haven
#

It looks to me like your SD got corrupted. I would recommend reflashing the card, or a different one, using the Raspberry Pi Imager.

olive pawn
#

Hi guys,
I am trying to get the serial data from an ultrasonic sensor (that is connected to my adafruit circut playground) to a raspberry pi. I am using the "Microsoft MakeCode for Circuit Playground Express" App on windows, and here is the code that I have

#

it shows the distance in the console log just fine, but i am having trouble with getting that serial data on a raspberry pi (or a computer). I have gotten a script from somewhere, but it doesnt seem to be working. Could someone help me with this?

#

here is the python code that i am trying to run:
#!/usr/bin/env python
import time
import serial

ser = serial.Serial(
port='/dev/ttyS0', #Replace ttyS0 with ttyAM0 for Pi1,Pi2,Pi0
baudrate = 9600,
parity=serial.PARITY_NONE,
stopbits=serial.STOPBITS_ONE,
bytesize=serial.EIGHTBITS,
timeout=1
)
counter=0

while 1:
ser.write("Write counter: %d \n"%(counter))
time.sleep(1)
counter += 1

umbral sable
olive pawn
#

import serial
ser = serial.Serial('/dev/ttyS0', baudrate= 300) # open serial port

while True:
print(ser.read())

#

here's what i tried^

umbral sable
#

That should generally work if it's the correct port name. Are you getting any errors or any output?

olive pawn
#

yeah im getting an output of: h ' '

umbral sable
#

Do you mean b''? An "h" doesn't really make sense.

olive pawn
#

sorry i misread it becasuse of the resolution. I am getting an output of b''

umbral sable
#

Cool, that at least makes a little sense. The read() function returns a bytes type, so that's what Python is printing out... an empty string of that type (prefixed by "b" to indicate bytes).

#

However, it's a little unexpected that it would do that, since normally read() should block until it has some data to return.

olive pawn
#

stopbits=serial.STOPBITS_ONE, bytesize=serial.EIGHTBITS

#

perhaps i have to add this^^?

umbral sable
#

Those should be the defaults.

olive pawn
#

hmm

umbral sable
#

Is it just printing one b'' or continuously?

olive pawn
#

continuously

umbral sable
#

That sounds like the timeout value has a different default, so maybe pass timeout=None explicitly.

olive pawn
#

sure lemme try that

dry galleon
#

i've recently tried out NodeRed on my raspberry pi. Turns out it works better than expected and i want to keep using it as an NodeRed/Mosquitto server. Problem is, that the raspberry pi was used for Octoprint and i don't have a second one spare so now my 3D Printer has no raspberry pi anymore.
Is there a way i can run Octoprint, NodeRed and Mosquitto at the same time on the same pie? or do i have to buy a nother one?

olive pawn
#

no b''

#

@umbral sable do you know the best way to find the serial port for my adafruit?

#

cuz i got it from doing dmesg

mystic light
#

your serial port isn't receiving anything and since you set the timeout to None, it's just sitting there waiting.

olive pawn
steady rose
#

unplug the circuit playground

#

run dmesg -w

#

plug in the circuit playground

olive pawn
#

ok lemme try that

mystic light
#

somebody put out a bunch of serial port tools that have utilities to list out the CP serial ports

olive pawn
#

but what should i look for, there is such a great difference

mystic light
steady rose
#

it doesn't look like any serial devices entries are being created

olive pawn
steady rose
#

post screenshot after plugging in

olive pawn
#

this is after

steady rose
# 
[ 3592.022189] usb 1-1.2: new full-speed USB device number 7 using xhci_hcd
[ 3592.160672] usb 1-1.2: New USB device found, idVendor=03eb, idProduct=2402, bcdDevice=42.02
[ 3592.160682] usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 3592.160690] usb 1-1.2: Product: CPlay Express (app)
[ 3592.160697] usb 1-1.2: Manufacturer: CPlay Express (app)
[ 3592.160704] usb 1-1.2: SerialNumber: 1763391388
[ 3592.171639] hid-generic 0003:03EB:2402.0005: hiddev96,hidraw0: USB HID v1.00 Device [CPlay Express (app) CPlay Express (app)] on usb-0000:01:00.0-1.2/input1
#

still no serial devices entry being created

olive pawn
#

huh that is weird

#

and i have the serial turned on by doing raspi-config>Interface options>serial port>enable

steady rose
#

the issue is with whatever is running on the circuit playground

#

it's not generating a serial port connection with the pi over USB

olive pawn
#

hmm

#

this is the code that i am running on the circut playground

unknown.png
#

i found it the easiest to do with block codes :/

#

(cuz i do have a circuit playground bluefruit but didn't want to code it in circuit python, thinking it'd be harder)

mystic light
#

you'll probably get more help if you're using circuitpython to program your board, since that's what people are familiar with

steady rose
#

yah, sorry, i also don't know much about the serial block in makecode

#

it may be specific for use with the associated app

olive pawn
#

can you tell me what specifically im looking for when I do dmesg -w?

steady rose
#

it can vary, but typically a message indicating a device with tty in the name

# 
[1301527.849206] cdc_acm 2-1.5:1.0: ttyACM1: USB ACM device
olive pawn
#

ok thank you

steady rose
#

^^ try that

#

written in arduino. prints "Hello world!" every 500ms.

#

but can use to test behavior on the pi with known working serial code running on the CPX

olive pawn
steady rose
#

it won't open in makecode

#

put CPX in bootloader and drag UF2 to BOOT folder

olive pawn
#

ohh ok

#

so i put the file into CPLAYBOOT

#

and connect the adafruit to my raspi

#

i dont think im still getting the signal

steady rose
#

i get this:

[  258.484788] usb 1-1.1.2: new full-speed USB device number 5 using dwc_otg
[  258.627227] usb 1-1.1.2: New USB device found, idVendor=239a, idProduct=8018, bcdDevice= 1.00
[  258.627250] usb 1-1.1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[  258.627267] usb 1-1.1.2: Product: Circuit Playground Express
[  258.627282] usb 1-1.1.2: Manufacturer: Adafruit
[  258.627297] usb 1-1.1.2: SerialNumber: 85C4C413504C5435382E314AFF02132C
[  258.708548] cdc_acm 1-1.1.2:1.0: ttyACM0: USB ACM device
[  258.710843] usbcore: registered new interface driver cdc_acm
[  258.710859] cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters
#

/dev/ttyACM0 would be the serial entry in that case

# 
pi@raspberrypi:~ $ cat /dev/ttyACM0
Hello world!

Hello world!

Hello world!

Hello world!

Hello world!
#

^^ try that one. it adds neopixel animation so you'll at least know the code is running on the CPX.

olive pawn
#

what i am doing is downloading this file and copy and pasting it onto the CPX. The green led is animating, and i plug it into my raspberry pi (through the usb port)

#

still i only get this

steady rose
#

are you copying the UF2 to a folder with BOOT in the name?

olive pawn
#

there is no boot folder

steady rose
#

how do you upload UF2's downloaded from makecode?

olive pawn
#

just press the download button and it automatically puts it

#

or i download the UF2 file and drag it to CPXPLAYBOOT

steady rose
#

that folder

olive pawn
#

yeah that drive

steady rose
#

it has BOOT in the name

olive pawn
#

i thought it was folder ohh

steady rose
#

drag the UF2 to that folder

olive pawn
#

yeah that ejects my cpx

#

and then plays the animation

#

then i take it out of my computer

#

and put it into the raspberry pi

steady rose
#

if the neopixel animation is playing, then the code has uploaded successfully and is running

olive pawn
#

yeah

steady rose
#

does the animation play again when plugged into the pi?

olive pawn
#

yep

steady rose
#

do you see a message like this:

[ 3310.994861] cdc_acm 1-1.3:1.0: ttyACM0: USB ACM device

in dmesg output?

olive pawn
#

nope :(

steady rose
#

weird

#

what model pi?

olive pawn
#

4 b

steady rose
#

what os are you running?

olive pawn
#

rasbian

#

i even put it in a google doc and searched for tty

#

the only ttyAMA0 that shows up is this one

steady rose
#

those are other things

#

not sure why it's not working

#

just tried a pi 4 here

#

and it works fine

# 
[   62.464641] usb 1-1.1: New USB device found, idVendor=239a, idProduct=8018, bcdDevice= 1.00
[   62.464664] usb 1-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[   62.464682] usb 1-1.1: Product: Circuit Playground Express
[   62.464699] usb 1-1.1: Manufacturer: Adafruit
[   62.464716] usb 1-1.1: SerialNumber: 85C4C413504C5435382E314AFF02132C
[   64.232937] cdc_acm 1-1.1:1.0: ttyACM0: USB ACM device
[   64.236127] usbcore: registered new interface driver cdc_acm
[   64.236145] cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters
# 
pi@raspberrypi:~ $ uname -a
Linux raspberrypi 5.10.103-v7l+ #1530 SMP Tue Mar 8 13:05:01 GMT 2022 armv7l GNU/Linux
olive pawn
#

[ 2.306125] usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 2.306145] usb 1-1.2: Product: Circuit Playground Express
[ 2.306162] usb 1-1.2: Manufacturer: Adafruit
[ 2.306179] usb 1-1.2: SerialNumber: E91B379C504B3233382E3120FF0F042B

#

yeah this is all i get

#

nothing after the serial number

#

let me try another usb cable

steady rose
#

and other USB ports on the pi

olive pawn
#

[ 31.832647] cam-dummy-reg: disabling
[ 227.890052] usb 1-1.2: USB disconnect, device number 3
[ 235.816817] usb 1-1.2: new full-speed USB device number 4 using xhci_hcd
[ 235.965978] usb 1-1.2: New USB device found, idVendor=239a, idProduct=8018, bcdDevice= 1.00
[ 235.966009] usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 235.966030] usb 1-1.2: Product: Circuit Playground Express
[ 235.966048] usb 1-1.2: Manufacturer: Adafruit
[ 235.966066] usb 1-1.2: SerialNumber: E91B379C504B3233382E3120FF0F042B
[ 235.974061] cdc_acm 1-1.2:1.0: ttyACM0: USB ACM device

#

WAIT

#

I THINK ITS THAT ONE

#

[ 235.974061] cdc_acm 1-1.2:1.0: ttyACM0: USB ACM device

#

and its printing hello world!

steady rose
#

cool. yep. that's it.

olive pawn
#

i think it was the usb cable :(

#

thank you so much for helping

steady rose
#

wow. really weird. the cable worked well enough to show the initial connection.

olive pawn
#

thats super weird

steady rose
#

usb cable issues are a thing, unfortunately

olive pawn
#

:(

#

now just gotta fix my adafruit code for the signal

foggy onyx
#

Was installing emacs but now its suddenly got stucked :(

20220331_144745.jpg 20220331_144802.jpg
#

What should i do now ???

#

Key board and mouse are not working

#

Every thing is stucked

foggy onyx
#

Then i removed power supply and rebooted it

#

Then i got

20220331_151310.jpg
#

Then i use second sd card (flashed yesterday)

#

And i got

20220331_151520.jpg
#

Why my sd cards are working for sometime and getting corrupted ????

#

Some please help me

#

I was just seeting up my sd card

#

It was stucked from many hours

#

So, i did it

foggy onyx
#

Struggling from last night before of problems

zinc jackal
#

I'm just waiting for a micro USB to USB-A hub to arrive, so I can use my Pi Zero 2 W. 😎

faint sparrow
#

Could anyone help me with ST25DV16K NFC tag? in the beginning it all works fine as I tried to write information like url and text with an NFC app on my iphone, but then at some point the NFC stops working and the app says the tag is not supported, So I guess i made it corrupted somehow, is there anyway to fix it?

slender meadow
#

Hi All, would this be the correct place to ask about a project i am stuck with using a PI to count pulses from a hall effect sensor on a water meter?

#

Hi Ed lol

steady rose
slender meadow
#

thanks

#

I have a pulse generator, generating 270Hz at 50% Duty Cycle. It reads correctly on a third pard "built" counter, but for the life of me I cannot get a pulse count anywhere close on the PI. I have Ubuntu running on the PI and dont know whether to use C or Python3 for the project? I have a small DSO and can measure the waveform, getting a perfect square wave at 269Hz.

I have googled and asked on forums and keep getting told to use this library or this is something similar. I cant believe there is nothing clear cut out there, am I asking it wrong? lol. I can show the latest iteration of my python test code?

kindred tangle
#

I just posted a huge message and it was instantly deleted lol.

#

Does anyone know how to get in contact with Tony DiCola about his RGB Matrix Mirroring software? It's been incompatable with the Pi4 for over a year now, and its a very useful piece of software that's allowed me to make really cool RGB clocks.

steady rose
#

looks like the bot flagged it for a banned word

kindred tangle
#

It might have been because i posted an external link or something.

#

Oh ok.

#

This was his software 😄

lost wolf
kindred tangle
#

Ah thats probably why he never answered any of my emails lol.

lost wolf
#

That would do it, yeah. 🙂

kindred tangle
#

Maybe someone should eventually look into porting it, because its very useful for dumb dums like me with the software side of things.

#

Might help the sales of the HAT+RTC/Bonnet too 😛

lost wolf
#

Other than Pis being unobtanium.

kindred tangle
#

Im going to start using that word more often rofl! Ive been scouring ebay for 3B/3B+ models for the time being.

lost wolf
#

Oof yeah.

kindred tangle
#

Big oof indeed.

#

@lost wolf Anyhoo, thanks for the response! And i hope some gifted programmer eventually updates it.

lost wolf
kindred tangle
#

Rgr!

frail rapids
#

We keep getting this error message, as far as we know everything is wired correctly. Any ideas? We’ve tried swapping out our Raspberry Pi and BMP3 sensor, we’re using a Raspberry Pi 3b+.

IMG_6819.png IMG_6818.png
civic rune
#

Have you tried an I2C scan?

frail rapids
civic rune
hardy plaza
steady rose
#

^^ seconding that. check wiring.

hardy plaza
#

Missing power or ground, SDA and SCL swapped, pins shorted somewhere. The i2cdetect is scanning the I2C bus and clearly there is no working device, otherwise it would show up. Perhaps try adding another I2C device to the bus to see if it shows up. That would at least tell you if it's the device you're using or the bus itself.

#

The other thing that sometimes causes this is if the wires connecting the I2C device are too long. Under about a foot is usually okay, after that you're in the realm of gambling.

zinc jackal
dusty swallow
#

jo

#

does german support exist?

#

i have a problem with adafruit_hid i want to change keyboard layout do german but it dosnt work

rain fulcrum
#

Really strange Wi-Fi 5g connection issue with a brand new Pi400. Is this a known issue with Bullseye 32bit and 64bit? I haven't tried another OS or the Raspberry Pi OS (Legacy) version yet.

° Fresh install of bullseye 32bit or 64bit
° I went through the initial setup.
° Wi-Fi Country set to US.
° Selected my 5g wireless AP.
° Downloaded the updates supplied.
° Rebooted the 400 and my 5g access point will not connect. Nowhere to be found on the dropdown list. Other 5g access points (not mine) show in the dropdown.

Has this happened to anyone else?

foggy onyx
#

i install as they said

#

but p10k command is not workinh

olive pawn
#

hey @steady rose