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Multiway 230v light switch + IoT relay

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Newbie level 4
Jun 14, 2015
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Hello all!

I have a question regarding connecting a relay to a light switch, and controlling it wirelessly with an Arduino. The relay I have is this one:, I have previously successfully used it to turn remotely turn on/off a smoke machine (only using two contacts for on/off). I have a light switch in the wall that is only a single switch with 2 wires, but in the wall are actually 3 wires connected. I would like to change this switch to a multiway switch, hook it up to the 3 wires through the wall, and between the switch and wire install the NC/Com/NO relay, and also additionally power a wall wart that powers the relay... I'm not 100% sure that I can use diodes this way (and think i actually cannot, but I need to be able to somehow power the wall wart, and there is no other way to do it (batteries are too big, and there is no extra power cable).

2015-06-27 21.17.09.jpg

This diagram that I can made, is it correct? Incase it is not, could you please elaborate and explain how to properly connect these?

Thank you in advance,

- - - Updated - - -

Just forgot to mention that I live in the Czech republic, so the circuit is at 230V.

No it won't work as drawn. You are rectifying the AC that goes to the "Wall Wart".
This won't work since the WW needs AC.
See my modifications to your drawing.


  • 2 way sw.jpg
    2 way sw.jpg
    1.2 MB · Views: 80

Hi ljcox,

Thank you for your reply. I understand that the easiest solution would be to get the power for the wall wart straight from the source, but because of the construction and length between the two this isn't possible.

I thought that using diodes wouldn't be possible because of AC/DC... is there a way around this? Because if I connected both wires straight to the wall wart then I would close the circuit thus permanently turning it on... I would need some sort of solution so that the wall wart is permanently turned on, thus giving the relay permanent power...

Since you did not correct the rest of the circuit, I am hoping that it is fine?


Still didn't figure out a workaround. Any additional help?

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