I have a remote controlled battery box (Lego) that I want to use to control a relay module. Having limited electrical knowledge and tools, I opted for a ready made relay module (bistable, because I don't have a continuous power source).
The issue I have is that the module I purchased has separate contacts for the relay's power and the two buttons to control it:
My battery pack only provides power until the button is pressed but allows to reverse the flow. Playing around with the module I found that I can make it work by plugging DC+ to the IN connector (lower outlet) and DC- to one of the COM outlets.
My solution would then require plugging two different wires (corresponding to two buttons on the RC) to the IN connector + and then one - to each COM.
Am I right that I will need something (e.g. zener diodes) to prevent the current flowing backwards to the controller? Something like this would work?
EDIT: I'll try to clarify. The relay module itself works with any polarity and has protections in place. It works both when powered as intended (first picture) or powering one of the two IN and COM. The problem is my RC controller: I one plugged some LED directly and it started to smell (I probably fried something). I imagine that connecting the + from two different lines of the RC together would be bad for it, so I need to prevent that?
Edit 2: here is a picture of the RC box. It's meant to control motors or lights but I would like to use it to control the relay.