"in-wall" switch and "in-ceiling" relay... advice please :)

[ben999]

Hi Folks

I am designing an in-wall switch to suit my needs :

• a touch-switch with relay (to control lighting) from a single location
• a touch-switch without relay (sending ON/OFF command to the gateway) so i can expand the previous design to a 2-way, 3-way, x-way system

My house has been built in the late 70's... meaning the wall boxes are fairly shallow.

So far, the second design fits in the wall boxes.

But adding a SSR looks very difficult from where is stand (with my tools and knowledge)

Idea of the moment is : how about adding a node (with relay) in the ceiling, where the lighting is suspended ?

Any pros and cons ?

Thanks for reading !

[gohan]

If you have room in the ceiling, it's a good solution, the only problem I see is that it is not very easy to reach in case you need to do any maintenance (ota updates are quite a must in this case)

[sundberg84]

@ben999 - I suggest you search the forum. There are alot about this.
Also openhardware.io has alof of ready project you can take inspiration from.

[ben999]

@gohan and @sundberg84 thanks a lot for your replies

@sundberg84 sorry i didn't explain enough. It was more like "would it be safe to do so"...

My current project is highly inspired by Aproxx's work
https://www.openhardware.io/view/77/AC-DC-double-solid-state-relay-module
So i use a varistor, fuse and thermal cutoff, but would it be enough ?

I just don't fancy burning the house down...

[sundberg84]

@ben999 - same there, this has been discussed alot!
Have a look here about safety:

• http://forum.mysensors.org/topic/1607/safe-in-wall-ac-to-dc-transformers
• http://forum.mysensors.org/topic/1540/110v-230v-ac-to-mysensors-pcb-board
• http://lygte-info.dk/review/Power Mains to 5V 0.6A Hi-Link HLK-PM01 UK.html
• https://skippy.org.uk/quick-look-at-the-hlk-pm01/
• https://www.ieee.li/pdf/essay/safety_considerations_in_power_supply_design.pdf
• https://forum.mysensors.org/topic/4175/clearance-creepage-and-other-safety-aspects-in-mysensors-pcbs

A recent one: https://forum.mysensors.org/topic/7919/which-are-trustworthy-brands-for-a-simple-usb-wall-charger/

The issue will always be that a DIY AC/DC powered node will not be covered with any insurances or so. Its possible to do the safe but without any CE/FEE markings you are not covered... and even a safe product can fail.

[dbemowsk]

@ben999 I have a number of switches around my house that I designed myself. They don't have relay control. They just talk to the automation controller and act as basically a scene switch. If you are in the US, this may be an option for you. Here is the thread that talks about it.
https://forum.mysensors.org/topic/4317/us-decora-style-wall-switch/34

The way I have mine set up, the switch talks to my Vera controller, and my Vera uses scenes to talk to another relay controller on the light/fan/device that I want to control. Many of the relay controllers that I have are Sonoffs. The response from switch to Vera to Sonoff is near instantaneous.

The switches that I designed consist of 3 boards. The power supply board, the controller boardf (arduino pro mini + nRF24 radio) and the switch board. The switch boards that I designed is universal and can be made as a 4 button, 2 button or single button switch. I also have 3D designs for the switch plates that I made. These can be found on my thingiverse page. https://www.thingiverse.com/dbemowsk/designs.