KinCony KC868-A16 added with additional 16 relays board

[stray glacier]

KinCony KC868-A16 16 IO board boosted with 16 channel relay board, linked together with I2C PCF8575 module.
This is retrofit to control my house lights. Currently have 24vac push buttons with status led's to control impulse relays. In new setup push buttons are connected to KinCony board input's, MosFet outputs feed 12vdc to button led status info and relays are controlling impulse relays if needed - if there's smart lights impulse relay is NC stage and lights are controlled directly. In case of API and/or MQTT is down board goes to failsafe mode and control relays -> impulse relays and switching light on/off like today in non smart world.
There will be timing's for short & long push. There will be 2 identical set's to control all current light groups.
Configs are still in progress, but thanks to @proud ginkgo there will be globals & scripts in use to simplify & reduce of duplicated line items

KinCony KC868-A16 added with additional 16 relays board

[high wadi]

Wow, that's going to be a lot of wires in a tiny space! But love the principle. It's like having a PLC but powered by ESPHome.

[vocal saddle]

cool stuff, I'm super interested on this as I'm planning to build a home in the future.

I was just wondering how this would work with the physical switches? If I'm not mistaken you will have to wire the switches to this board... wouldn't that add a lot more of wire? Or am I wrong?

Also do you plan to have these boards in one place where all the main switches are or there will be several of these throughout the house?

[stray glacier]

That failsafe config is important part of whole setup

I do have existing physical wall switches, or actually those are buttons and wired already to electrical cabinet.
Now I’m moving wires from existing termination point to board

All switches aren’t wired independently to one location, but grouped and patched per light group.

[vocal saddle]

Sorry didn’t quite get that! Do you mean you use several of these boards around the house so you can group lights and don’t need to wire all to a main location?

[stray glacier]

No, all switches are wired to single location, but not separately. That means for example in living room I do have 8 buttons panels in 4 locations, but those are patched together and wired out from that room as single 8 button panel. Due existing cabling and the way how those are made I can’t modify each button individually, but just group of buttons what are operating as parallel

[proud ginkgo]

Yes you would wire all switches back to one location, and yes this means more wire. But for the switches, you can use cheaper low voltage wire as they are simple signals and dont need full AC wiring

[vocal saddle]

ok got it, then it's more or less what I was thinking. I was wondering if there was a "better" way to avoid wiring every switch back to the main panel but I guess it's the only option if you want to control everything from there.

Wondering why not use solid state relays tho?

[vocal saddle]

Just saw this board outputs 12/24v. How do you handle voltage drops on long runs?

[wintry hedge]

It depends on where the power is going. If it's low current, there's very little voltage drop.

[high wadi]

Exactly... you don't care of the minimal voltage drop there might be if you're just lighting a LED or getting the state of a push button.

[stray glacier]

It’s just to light led on and using 24Vdc it doesn’t matter If voltage drop is 70% as even then it voltage need to drop down inside of switch to proper level

[vocal saddle]

gotcha, then I shouldn't be worried about long runs of 24v to drive my analog LEDs. I wanted to use mosfet instead of relays so I can control brightness while the leds are also high CRI

[wintry hedge]

Single LEDs or strips?

[vocal saddle]

strips, more precisely these are the ones I bought https://es.aliexpress.com/item/4000513067134.html?spm=a2g0o.order_list.0.0.37cf194d0Y1s68&gatewayAdapt=glo2esp

[wintry hedge]

A strip can take a lot of current. You will definitely have to consider voltage drop for that depending on how long the strip is.

[vocal saddle]

the only thing I can think of is to put the AC to DC transformer near the strips, but that also means I will have to put the mosfet in between, so it won't be all in a central place

[vocal saddle]

I created very ugly diagrams just to make sure I'm getting it correctly. One is the "regular" installation with the relay behind the light switch.
The other is doing the same but in a centralised place. Initially I thought you would only need to use more wire to get it into the main switch panel, but I'm also realising that you also need to run the live for the bulb independently as well

[proud ginkgo]

yes, every light bulb/group will be a whole circuit to the main panel.
Basically the tradeoff is between paying more per individual switch with regular wiring, or paying for a single automation controller like the A16 etc which costs less, but you pay for more wiring and it could come out cheaper in the end

[vocal saddle]

I think I prefer the centralised idea, I can have ethernet to those modules so it will be way more reliable as well

The only down side seems the voltage drop and if it ends up being a problem, then I won't be able to have centralised place for relays, mosfets to regulate the LED strip intensity, etc

[proud ginkgo]

yeah I see how that could be an issue.
Putting a power supply by each strip (or a group of them) and adding the mosfet to each strip would not be a whole lot of extra work though

any way you do it, you still only need to run a pair of wires to the area the strip is at

[vocal saddle]

what I mean is that if the AC to DC transformer is in the main switch panel, but the LED strips are far away (supposedly suffering for voltage. drop), I will have to move the transformer closer to the strips and out of the main switch panel... and because the mofset board has to be in between the strip and the transformer it won't be in the main switch panel either (unless there's another solution, I'm super ignorant on these topics)

For the AC lights or other appliances should be ok tho

[high wadi]

With AC at higher voltage, currents are a lot lower than low-voltage DC, so your wires can be thinner (for the same power loss). E.g. For 10A, on a 10m run, if you want to keep your voltage drop around 2V you'd need at least 14AWG or 2mm^2 and even then you'd be dissipating 20W on the wire (2W per meter) so you lose all that in your lights efficiency.
Using the same wire in AC, you'd have around 1A (assuming 240V) dissipation would go down to 0,2W (0,02W/m), that's 100 times less power loss.
So, yes, the advice is to have DC wire runs as short as possible, and use thicker wires.

[stray glacier]

some progress, finally got enclosure modified and board is now installed inside. Relay board also got some modification. pinheader and and one capacitor moved underside. PCF8575 board also is slimmer than before.