Controlling Shelly with a relay

  • Hello!

    First of all, I know a similar problem has already been discussed in this topic, but I'd like to hear your suggestions on how to properly address it.

    I'm planning to install touch wall switches in my apartment. With remote control and automation in mind, I figured that it would be perfect to match them with Shelly 1 (for 1 gang switches) and Shelly 2.5 (for 2 gang switches). However, the switches I've chosen don't have neutral line connections, so their line outputs are never really zero (neutral effectively goes through load). This means that Shelly will always recognize this as a high switch state.

    I tried reducing the non-zero low switch state using resistors to no avail. It seems I need to use other electronic components, such as relays or triac-based circuits, to drive the Shelly's SW input.

    Even though I have some basic experience with assembling simple circuit boards, I'd prefer to use ready-made devices, mainly due to safety concerns.

    My current idea is to put an AC-AC SSR (or perhaps another type of relay?) between the touch switch and the Shelly, as in the diagram below:

    shelly_touch.png

    But how can I make sure that the same thing doesn't happen to the relay, i.e. seeing the touch switch output as constantly high? This should probably involve carefully picking a suitable relay with a matching driving current and voltage, but I don't really feel confident I would make the right choices.

    My other problem is limited box space, so any additional elements should be as compact as possible. And then there is the potential issue of interference when relays are packed too close to one another...

    Anyway, I would really appreciate some insights and suggestions. My primary goal is to have touch-controlled switches which work independently of network conditions, so that manual operation is always possible. But then I also want them to be controllable over Wi-Fi (preferably over LAN), enable custom automation possibilities and feature modular design. My current pick would be perfect if only I had a reasonable way of making it work with Shelly :(