POE /DC Wall Switch as Secondary to Tuya Wall Switch

Hardware
1

Hi All,

I had two way switching in my lounge room for the lights with mechanical switches. I have recently replaced the main switch with a smart switch but the mrs doesn’t like it. I have got a remote Tuya button that I have placed near where the other switch was but my mrs really wants the original mechanical wall switch in the 2nd location.

As such I am looking for something I can wire direct to a mechanical wall switch that senses change in state (On - > Off) and then via Tuya / Smartlife will communicate with the other main switch and tell it to change state. Ideally I want a device that I can place in the wall and power via DC power or POE. I have found some that are mains powered but I then have the issue of 1. needing to get an electrician to do it and 2. Compliance with Australian standards.

Note: There is the possibility that as the switch is pushed to its other state there would be short bursts where it flicks from one state to the other. As such would need something that can handle this type of signal noise (debounce delay).

Any advice would be appreciated.

2

Trip down to Bunnings should get you this switch that can be wired for two way operation. Tuya / Smartlife compatible. Install one at each end and let automation take care of the switching. Mains powered, assuming you have the usual active/ neutral/ earth wiring available to your existing switch, like most Australian Standards compliant house wiring does. Sparky should be able to install them in a few minutes - a simple swap for existing switch. Instructions in the packet. Note the two way capable switch (the one you want) is actually cheaper than the simple one - strange! SWMBO will absolutely love the pale blue glow to be able to find it in the dark.
https://www.bunnings.com.au/deta-grid-connect-smart-single-gang-2-way-touch-light-switch_p0346910

3

The switch that is needed needs to go in a architrave mount (really only wide enough for a standard size mechanical wall switch). We had a 2 gang and I had it changed to a single (other switch is for outside) so really need something that goes inside the wall and don’t really want to have to have to get another electrician out to do it either. I have a POE port just beneath the floor here so could run that up the wall and also have a step down splitter to drop voltage to either 5 or 12V so that is my ideal option.

I think something like these Sonoff ones would work but these are mains powered and I want to run off low voltage DC

I am assuming even though this is designed to have a load connected to it that it would work as a remote switch also but the required supply voltage is the problem

4

You need a relay with dry contact. Something like the Shelly 1 will work for your scenario.

5

Sonoff mini-d or Shelly 1 can be powered from 12-48 VDC

6

just leave the two way switches as is, and place a shelly near the light….configure the shelly to ‘toggle’, and that’s it…

Shelly’s can be powered by DC, but that makes it rather complicated.

Really weird you need an electrician in down-under (they can make mistakes just like any other… I personally always verify someone else’s work before powering on :face_holding_back_tears:)

LOL…just did some reading on it (because in the Netherlands DIY is perfectly fine), turns out that statistically in Australia there are not less accidents then in the Netherlands, turns out most accidents are made by workers :woozy_face:

7

Ok in doing more research based on my understanding now of needing a “dry contact relay” I have found I think an option which also includes my desire to have it run on low voltage DC (so can power via POE) but also ability to be in the Tuya Ecosystem as like to not have to bridge things between technologies where it isn’t needed and have discovered Shelly and Sonoff are their own locked systems (mostly).

If someone is able to confirm my theory I would appreciate it. Many Thanks.

And Sadly yes there are many shonky things I have had done in my own house by Electricians (some of which I have then paid other electricians to come and remedy at a later date) but from a insurance perspective if you ain’t licenced and do mains voltage house work and something happens your not covered. Kind of a different story with non fixed things (such as appliances that can be pulled out from a power point). But yes that is the regs (loosely) that we deal with here

8

The Arlec ones I recommended also have dry contacts inside their switched relays, and onboard power supplies. Same size as standard wall switch and a drop-in replacement. No POE wiring needed. Don’t over-complicate things and have to pull added cable, especially if it is behind walls filled with insulation like is common in more modern houses in Australia, and the yellow-tongue gets stuck on the noggins. If the slimline aspect is an issue, just replace it with a blank cover and install the new one adjacent in the wall - the wires should stretch. Remember you are paying your sparky by the hour, and the time required to simply swap over a familiar looking switch with another that also looks similar and just move the existing wires to the new unit, compared to reading Chinglish instructions and pulling added power wires is going to quickly sway the financial aspect.

You will find as you research even further that most automation light and power switches have a relay with dry contacts, as it is the cheapest way of switching mains power reliably and in a small package.

You do realise whatever device you connect, behind the wall or not, dry contacts or not, you will still be connecting the mains power to switch it, and the electrical connection work will need to be done by an electrician?

Have you checked out the SwitchRoo also described here in these forums? They may also offer a light switch version of their Deta modfed devices you also find at Bunnings. Support your home grown industries.

Your own custom firmware? The older versions had a ESP, and more recent ones have a Tekin chip on board. Both flashable for Tuya independence, and integrate well into HomeAssistant.

Both devices you have referenced sourced from AliExpress may not have the obligatory RCM certification, confirming your thoughts that no matter how attractive they may be in price, no electrician that is legally required to issue a certificate is going to risk losing his career by installing it.

Grumble, pay the ‘Aussie’ tax, get something compliant, fitted by an experienced professional, and sleep comfortably at night. Ask your family if the fifty bucks you save buying cheap Chinese stuff is worth it?

9

They have to place their career on the line, to issue a formal certificate of compliance, for each job they complete. Regulation can be a burden - time and cost wise, but from my personal observations, overall quality and standards are significantly higher than found in the US or Europe, some botched DIY wiring jobs showing complete ignorance of fundamental safety and wiring principles. Elimination of the cowboy aspect by enforcement has cleaned up their industry. Like finding a good doctor or dentist, once you find a trustworthy tradesman, stick to them.

10

I agree to disagree here, from personal experience, I see no difference in quality of work (at least in the Netherlands, can’t say much about the rest).

The same applies to the work done by some professionals :woozy_face:

11

You usually get what you pay for, DIY being free…

12

Great info there IOT7712,

Blocking that plate and placing one adjacent on the gyprock is not an option as I have a large piece of furniture there that can’t really be moved.

For clarity also it was a 2 way switching however with the installation of a smart wall switch at the other location (light connected to it solely) the wire and everything for the other switch was removed. I am using a remote zigbee scene button at the moment but the mrs. isn’t a fan of it and wants to revert back to the old mechanical switch which is mounted on wall where she is used to but also doesn’t want to loose the smart switch at the other location (which does fan control stuff also).

However in researching what you have stated about the RCM mark etc. which I am aware of from my previous industry background I didn’t think it would apply. In doing a bit more research it appears that given it would be powered by USB or low voltage DC that kind of means it can be utilised (although is in breach technically of ACMA due to the radio side but from a safety compliance perspective I believe I am all good).

Due to the low voltage and not looking to wire the light directly to it there is no contact with mains voltage and therefore no need for Electrician certification etc. It appears the key requirement for insurance and safety regulation is that it is attached to a RCM marked power supply. It is really no different to running a POE network cable for a security camera really (with the exception of the zigbee radio transmitter and ACMA).

If that is really the only issue but looks like it will function I will plan to proceed.

If not and if you can suggest something I can wire direct to a mechanical button (which I can then exchange for a wall switch) that ideally operates on the Tuya platform I am all ears. Especially if it will run from POE or otherwise DC power supply as failing that it will likely cost an extra $150 or more to install it.

13

So many complicated options…
Just install another mechanical smart switch at the remote location. (I like the Zigbee switch from Moes). Wire the traveler to always be hot. No load on the new switch, it’s just there to tell Home Assistant when it is toggled.

14

Sadly, I don’t think that has the obligatory RCM certification, an obstacle that most other countries do not have to carry, similar concept to FCC certification for the US for any devices that have any radio emissions.

RCM Mark << - this is what to look for - the C-tick

This one popped up when I entered a search into Google. It may not suit @naigy81 needs as it is not slimline vertical architrave mounted and not the same shape as the common switches found in Australia, but is clearly identified as RCM compliant https://forgeelectrical.com.au/zemismart-1-gang-saa-l-n-smart-switch-zigbee-white.html and is $5 cheaper than the Amazon one you linked to. There may be others out there where the importer has taken the effort to gain certification, (and expects to be recompensed for the effort and expense to do so - also known as the Aussie Tax amongst Home Automation enthusiasts). This is also discussed extensively in the thread here: Australia - Electrically Certified Hardware and also over at WhirlPool forums,

The MOES switch is 72mm wide and 118mm high. The standard slimline architrave switch found in Australia is 35mm wide and only 75mm high, or 32mm by 68mm. Clearly not a straight swap, and why they are not popular in Oz, or with SWMBO that has to operate it.

Note @zemismart is also on these forums. Zemismart Devices List That Work with Home Assistant ZHA and they claim HomeAssistant compatibility on their website Compatible with HA (ZHA / Z2M / Matter)
Disclaimer: I am not associated with them in any way, and your experience may be different to other vendors, other products, and other integrations. I just know their documentation is easy to follow and contains enough info to solve most challenges when installing.

The SHELLY 1 MINI GEN 4, Smart Home Australia may also fit the bill, hiding it in the wall cavity, using your existing architrave switch wiring as the input to the Shelly, and also to power it, no POE required. Also certified - see https://drive.google.com/file/d/1BnIgkH15watdgcgyjcCLNb4MCkeIF5nx/view?usp=sharing but your sparky will still need to do the wiring.

Also see Sonoff Zigbee Smart Relay Switch | SmartHome which may tick all your boxes at $19.00 - more details at the Sonoff site. SONOFF ZBMINI Extreme Zigbee Smart Switch ZBMINIR2 Your existing functional two way switch requirement is shown in the wiring diagram - the right hand one at connection diagram your sparky will easily be able to follow - note only one Sonoff device per light is required, and you will not need to add or run any new wiring, so the major cost for the sparky will be the callout fee and time to complete the obligatory electrical safety certificate. Note that one is ZigBee - they also offer Matter compatible devices.

For those following along from overseas and not a frequent visitor to their friendly shores, Bunnings is a large hardware chain with conveniently located branches across Australia, similar to Lowe’s and The Home Depot in the US, and B&Q, Wickes and Screwfix in the UK. They also sell Home Automation products, RCM approved, but a limited range.