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#what’s happening
lethal gladeBOT
true cobalt
Why do you have a USB plugged into the ATTIny85 ? There should not be anything connected to the USB Port, it is only for programming
Also , you should not just "tap" the wires together, you need to connect a Momentary NO (Normally) open switch. The switch input triggers different functions, so tapping the wires together will not work correctly.
Also without an LED eye connected it is hard to tell what state the board is in.
stone crescent
Does a limit switch work?
true cobalt
Yes, you can use a limit switch. Here is the correct wiring for the limit switch:
As a test before you make any changes, I would do the following:
Step 1 - Remove that USB cable you have plugged in , it should not be there.
Step 2 - Only connect 1 servo
Step 3 - Connect the LED Eye
Step 4 - DO not connect the switch or switch wire
Step 5 - Connect power to the board
You should see the Servo move into the close position and the LED eye should flash and then turn on
stone crescent
Could my servos be broken?
true cobalt
What are you powering the board with ?
It should be a USB Power bank that is 5v (2.1A)
stone crescent
Yea pretty much
proven shore
if you didn't put more than 7 volts on those servo's they probably are still ok. they are made forRC and the receivers for those all run on 4.5-7.4 volts and they use a BEC , a stepdown voltage regulator for 5V or 6V to power the servo's, Electronic Speed Controller, 3 axes Gyro etc. most servo's can take 2x lithium-polymer batteries in series (that is 2x3.7V= 7.4V, so don't worry about the servo's, they are acualy a bit underpowered at 5V
it makes them a bit slower
actualy my graupner receivers all have a 3.6- 8.4V window
and the servo's get their + and- from those receivers, so they can handle it
in my pitt special 80 cm stuntplane i use 6 Volts on those same mg90s servos, my 1.8m width S-Bach x300 the same, but with larger MG996 servo's
true cobalt
Yea pretty much
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That does not really answer the question, what are the specific ratings on the USB power bank, there should be a label or a sticker on it.
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Did you follow the 5 steps I outlined above? What was the result ?
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Post a picture of how you have everything wired.
In order to properly assist, you need to provide more information.
true cobalt
@proven shore
Thank you for your input, however while most of it is correct, there is context and information missing, and not completely accurate. The original poster is asking for help with his specific AM6 board issue. I will outline some of your points, but this is not the channel for a continuing discussion that is not directly related to the user's issue.
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MG90s servos are rated for a voltage range of 4.8v~6V(maximum), with a Current requirement at peak torque of 1A (1000mA), however with the rise of multiple companies making clone variants of this servo, they are not always in specification. Everyone always focuses on the "Voltage" requirement and neglects the "Current" requirement which is equally if not more important. Driving an MG90s servo with 5v, and saying it is underpowered in not correct, as there are numerous scenarios & applications that exist. "Having the most voltage, does not produce the best outcome when talking about a wide variety circuits"
** For example An MG90s Servo running at 5v (1A) will produce more torque than say an MG90s servo running at 6v (.25A)** -
Your example references RC (Radio Control Model) applications, RC uses various regulators and current control system when driving it's servos. For example RC power systems an LDO or Voltage regulator to stabilize the power coming from LiPo power sources. For the Helmet motorization kits, they are using Microcontrollers (Arduino, ATTIny85, Raspberry pi, etc..) to control their projects. These systems generally operate on either 3.3v or 5v due to their digital logic systems. Hence why you would not want to exceed 5v on these projects.
@proven shore - Your comment about "so they can handle it" just based on the voltage seems to imply they cannot be damaged by anything else. The user's servo could have been damaged if the following other things occurred:
- Reversed polarity on the power input
- Incorrect PWM signaling to the logic controller board
- Defective Servo from factory, which has occurred with the currently sold MG90s "Clones" as the true Tower Pro brand are very difficult to source and are expensive compared to the clones.
- Improper hardware used when attaching the servo arm to the servo gear. If the incorrect screw is used it can be too long or have the wrong threading, which would damage the servo gear.
I say all this to say, thank you for your input, but some of the information you provided could confuse, or give the original poster conflicting data as to the troubleshooting for his specific ALISHA AM6 board issue.
Bear in mind many of these hobbyists are extremely new to this and electronics, they are still trying to learn basic theory.
Here is the Datasheet for the original Tower Pro MG90s servo, if you want more information.
graceful steeple
Can you take a photo of your entire wiring setup as well as a pic of the specs on your power supply?
Seeing the USB cable plugged into the ATTiny board... Did you try to upload code or something?
Can you plug in an LED to the LED eyes port? That can be a good indicator of what's going on. If they blink and then come on that means the code is working properly.
Also, wait about 10-15 seconds for the board to fully initialize.