Switching 230V without touching it (with self built HW)

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Hi forum,

I want to switch 230 Volt. However, I do not want to touch anything but low voltage devices.
This is for safety reasons and because the insurance won’t pay me nothing if I fiddle with my 230V installation.

What I want to do is the following:

RPI (5V) or mysensors switch (5V) -> 5V or 12V relais ->230V relais (which need 12V or 24V)

I want to us a switching power supply 230V to 12V supply and a 12V to 5V supply to provide the voltages.

I am now wondering, what would be the best solution, using standard 5V relais or SSRs.
I found these on ebay:

standard relais: http://www.ebay.de/itm/182106264321
SSRs: http://www.ebay.de/itm/172350947705?var=471173049353

For switching the 230V I would use something like this:
http://www.voelkner.de/products/164720/Relais-Baustein-1xum-Rt-12V-DC-788-303.html?ref=43&products_model=S71858&gclid=CNnFgMyX0s8CFYgy0wodS9wGXw

As I said, I don’t want to touch any of the 230V (even if I have experience with it). A professional would install the 230V side and I could then play with the low voltage side.

What do you think about this setup?

Thanks
Dom

Sure enough that’s enough relais?

Since I can’t switch the 230V Relais with the RPi directly, I need something in between…
I thought that relais would be a good choice. That’s why I am asking here.

Would a mosfet driver be better? Like this one:
http://www.ebay.de/itm/New-1-pc-IRF520-MOS-FET-Driver-Module-for-Arduino-High-Quality-/322247801881?_trksid=p2141725.m3641.l6368

But I would still need 12V and 5V supplies and the price is pretty much the same as a one channel Relais.

Thanks

I think the mosfet Driver is the better solution. Because when you use a Relais the 20mA what an arduino Output can handle is not much. Maybee it works with the Relais maybee not. And you should use a Diode (Freilaufdiode) when you use a Relais.

@V1per: Thanks for the info. Then I will order some and perform my tests.

@V1per said in Switching 230V without touching it (with self built HW):

Maybee it works with the Relais maybee not. And you should use a Diode (Freilaufdiode) when you use a Relais.

@Dom If you go for the relais option, I think the easiest is to use one of these relais modules (like the one you referenced in your post) as these already have the flyback diode and resistor and typically an opto-coupler integrated. I am using one of these module with various boards (Nano, Megam, Esp8266) without problems with different setups (Normally open vs normally closed)

You should get some standard relaismodules, most are 5V-12V tolerant on the input, however I use an ESP8266 with EspEasy which runs at 3.3V and it works fine. I switch 1x230V and 3x24V with the relais which are hooked up to my garden irrigation system (1 pump and 3 valves).
As @mwittig already said these boards feature an optocoupler which provide the necessary galvanic separation.

There are ready to use boards like this: http://tutorials-raspberrypi.de/raspberry-pi-relais-schalter-steuern/

These cards are also manufactured with terminal block for input. For many installations, this is a better solution.
https://www.aliexpress.com/item/8-Channel-5V-Relay-Module-Board-Shield-with-Optocoupler-Support-High-and-Low-Level-Trigger/32723391127.html

what about the sonoff device?
with a bit of tinkering you can run espeasy or espimatic on it. somewhere on the forum is a nice thread. will have a quick look for it

If it is considered wireless. Why not straight use H801? Has a 5x12V output.

@Wutu: thanks for that link! Didn’t know that device before…

@Dom you’re welcome.
I’d pulled out a box and I would use such a thing for DIN rail. Just a thought.
https://www.aliexpress.com/item/Hot-Sale-1-set-of-Simple-PCB-Circuit-Board-Mounting-Bracket-For-Mounting-DIN-Rail-Mounting/32593594825.html

This device appears to many professional for this purpose. DIN mount box.
http://www.ebay.com/itm/152252603160