njh Posted August 1 Share Posted August 1 Hi! I have all my light switches wired to switch 240v. This might be possible to change to low voltage, but I think it would be clearer and safer not to have different voltages on different switches. Does anyone know if it is possible to connect an optocoupler to the switch inputs of a Shelly Plus RGBW? Aliexpress has lots of boards like this, which slightly vary in design: https://www.aliexpress.com/item/4001158838073.html The bits I am not sure about: - Making sure the optocoupler supports 24v (which is what I am using with my LED strips) - It looks like the Shelly is using pull-up resistors internally, and then the switches connect the inputs to ground. - It looks like the optocouplers send high / Vcc on activation. I assume the modules are something like this, probably with a bridge rectifier on the mains input: Thanks! nick. 1 Quote Link to comment Share on other sites More sharing options...
Members thgoebel Posted August 1 Members Share Posted August 1 Obviously, the „black knob cable“ wasn’t added the the purchased parts package of Shelly plus RGBW PM: IMHO this should be considered by product managers… 1 1 Quote Link to comment Share on other sites More sharing options...
QA members TheRegister Unique Posted August 1 QA members Share Posted August 1 PC817 optocoupler used in these Aliexpress modules is up to 35V so should work fine at 24V. Not sure about internal pull-up resistor and its value but you can easily check that using a simple DMM. 2 Quote Link to comment Share on other sites More sharing options...
njh Posted August 2 Author Share Posted August 2 Think I will just go for it; order a Aliexpress module and see if it works! I shall report back... 1 Quote Link to comment Share on other sites More sharing options...
Members thgoebel Posted August 2 Members Share Posted August 2 It will work. A connection with Vcc (pull up resistor) is obsolete, cause the Shelly plus RGBW PM has an internal pull up resistor: 1 1 Quote Link to comment Share on other sites More sharing options...
Tester Posted August 5 Share Posted August 5 I test it with „black knob cable“ but it doesn’t work. Any idea why? I connect the cable as in the picture shown 1 Quote Link to comment Share on other sites More sharing options...
Tester Posted August 5 Share Posted August 5 With the „black knob cable“ it doesn’t work. I tested it today. Is there any idea why? I have changed the wiring incl. switch 1 to 1 from shelly rgbw2 to shelly rgbw pm 1 Quote Link to comment Share on other sites More sharing options...
Members thgoebel Posted August 5 Members Share Posted August 5 12 minutes ago, Tester said: I connect the cable as in the picture shown What picture, please? 1 Quote Link to comment Share on other sites More sharing options...
Members thgoebel Posted August 6 Members Share Posted August 6 (edited) Optocoupler „cable“ (delivered with Shelly RGBW2) is working fine with Shelly plus RGBW PM. Setup: Red wire of optocoupler connected to terminal I1. Black wire of optocoupler (same side as red cable!) to terminal GND. Both black wires of optocoupler (same side!) wired with a mains switch (push button type) like a lamp. RGB stripe and power supply as usual. Device profile set to RGB. Transition time and fade rate reduced to 1 second to achieve faster reaction. Edited August 6 by thgoebel 1 Quote Link to comment Share on other sites More sharing options...
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