I am building a haloween prop for a party. I need to switch 120 volts with a 4.5 volt signal from a motion detector.

I totally missed this one and it's way too late, sorry.

There would have been a few questions like do you have at least 20 mA of current at 4.5 V to drive something? Any other voltages available?

The design might have been a bit tricky, parts selecction wise, but basically I would have started with a 3-30 DC controllable solid state relay. May have added a ULN200x interface chip.


Sorry, I just totally missed it.