Zigbee DIY button with DC power supply

Hardware
1

Hello,

Would it be difficult to “make” some zigbee dc powered push button module ?
The goal is to reuse my wall switches (momentary push buttons) and incorporate a zigbee module that could be powered by some cabling running the walls from switch to switch.
The actual cable running from switch to switch is a 6G0,5. Once the actual switch system is gone, I could use those 6 wires to bring power.
I looked for days on the internet and didn’t find any zigbee module that could be powered by a small DC instead of the 230AC.
Maybe get rid of the AC part of an existing zigbee module would be easier but I never opened one of them to see if it is actually possible.

I would need up to 4 input by module.
I don’t need the relay part of the module I find online.

Thanks for your idea and suggestions :slight_smile:

Have a good day !

2

Why you want dc wiring instead of 230AC?
You could use battery powered SONOFF SNZB-01 ZigBee button and wire it to your existing (momentary) wall switches. Remove the battery and make 3V dc wiring.

3

Thanks for your reply.

DC instead of 230AC because of the size of the wiring.
This is 0.5mm² wire. I night melt them if anything happen. I would like to avoid putting my house on fire, if possible :slight_smile:

The sonoff button is a possibility but I would like to use my existing momentary wall switch (already in place).
Also, the actual button location are quite good. I would need to cover the actual button location to put the Sonoff button. Not really convenient :-/

4

I wrote:

Also, the wiring size for low voltage is higher than for high voltage. That’s the reason we use 230V instead of 12V in our houses. 12V wire for same power would be 20 times “thicker” than 230V wire.

5

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remove the battery

6

Ok !
Now I get you :smiley:
I guess I could order one and see if it could work.

About the power, I’m afraid of running high voltage in small wire. I get that an issue would come from a overload, not from the wire size but, anyway, 230V wires must be at least 1.5mm² to be rule compliant.

Thanks for your suggestion :slight_smile:

7

That’s ok, 230V can kill you, 3V not. And I agree for rule compliant.
I just commented about your concern of melting wires with high voltage. The truth is opposite. For 500W load at 230V you have 2.2 Amps on your wiring. For the same load at 12V you have 41.7Amps. Your 0.5mm2 wire would be ok at 230V, but would definitely melt at 12V.
Also DC voltage is more dangerous than AC voltage because of arching.
But for your low power low voltage button you don’t have to be worried about anything.

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8

About the Sonoff option.
I would need to multiply the sonoff devices for 2 or 4 button switches ?

9

Hello ,

Yup, it’s tuya and no-name branded, but it’s a tuya zigbee device with open contacts no ac power. I have some on my door locks and they do Z2M just fine.
https://www.aliexpress.us/item/3256802470547597.html.

10

You can use one of these and wire it up like Karosm showed.
https://www.aliexpress.us/item/1005005801587116.html?spm=a2g0o.productlist.main.13.24bb59a2Lb49rA&algo_pvid=a76ad479-ad88-40e9-91ee-f4d87cdb8d3d&algo_exp_id=a76ad479-ad88-40e9-91ee-f4d87cdb8d3d-6&pdp_npi=4%40dis!BRL!110.53!65.21!!!129.11!76.17!%402101e7f617228816213998752eb94e!12000034615032635!sea!BR!700889899!X&curPageLogUid=BuYa5DBNCVDM&utparam-url=scene%3Asearch|query_from%3A
Definitely bigger than a SNZB-01, but you’ll have 4 buttons with 3 functions on each

11

Good catches above.

At this point you need to clearly describe, how is the whole system being powered? You use zigbee to control separate zigbee relay, or you still need to switch 230VAC with these “buttons”??
There is too much room for confusion…

12

I will try to clarify :wink:
For the time being, the system in place is composed of

  • an analog bus going from switch to switch (6 x 0.5mm² rigid wire)
  • some address modules, connected to the bus, using momentary push button switched to get the “pulse”
  • some kind of relais, at the other end of the bus, in the electrical box, switching on and off the lighting points, all connected to the electrical box.

The actual “switches” do not physically switch on or off the power to the light. Instead, they are used to send a command to the relais.

My goal is to get rid of the analog bus (address modules and relais) and use Zigbee instead.

My plan is to use an IKEA Dirigera hub to link all components and make the lighting system available from HA. It could work even if HA is down for the basic functions but HA would help me build complex scene or scenario if needed.

  • I have found some nice zigbee relais that could be installed in the electrical box (to replace the analog bus relais).
  • I have the push button in my walls. They are basic but they are working nice and are the same design as the rest of the electrical sockets of the house.
  • I “just” need some Zigbee module that I can install in the walls, behind the switches. Those Zigbee modules could be powered by the current analog bus cables.

Does it make any sense to you ?

13

perfectly,
then SNZB-01 and the one walberjunior linked could be your choices.
You just use old wiring to supply 3V (or 3.3V) to them.
If you don’t have enough space behind the physical switch, you can use old wiring to locate your zigbee buttons to most convenient place.
You might need to solder the switch wires to zigbee buttons.

1 Like