Anyway, I looked up your Santa. Unfortunately I couldn’t find much technical information on it. I was hoping that there was some kind of test / try-me button that you could tap into easily.

I think I’d have to actually tear one apart to figure out how to trick it into activating whenever you wanted. The problem with sound-activated props is that you can’t just short out the microphone and have it activate.

One thing you could try is putting the relay contacts in series with the microphone. If it looks for changes in sound level as opposed to an absolute level it might work.

Another thing might be to hook a battery in series with a pretty big resistor and the relay contacts and run that into the microphone input instead of the microphone. That way whenever the motion sensor is tripped a small voltage gets sent into the microphone input and Santa might do his thing. Again I don’t know exactly what kind of signal the circuit responds to from the microphone, but it might work.

Another, decidedly more ghetto method would be to hook some kind of noise-making device to the output of the motion sensor and place that right next to the microphone. Hide/enclose the whole thing somewhere so that people will hear Santa and not the noisy thing.

I hope I’ve at least given you some things to try.