help with interactive audio project

Greetings,
I am working on an interactive audio installation. I intend to trigger different sound samples from my laptop, and a hardware sampler, using analog signals (e.g. motion detection, light detection, etc.). I have an analog to midi converter that will run my samplers. But there is one problem, the analog inputs will only take "free contacts," I guess this means basic switches. The interface's manual specifies that no voltage should reach the terminals of the analog inputs. Because I want people walk through an area, I can't use typical contact switches.

I guess this sounds like a simple presence detector project, but I am not sure about the type of contacts I can use to run my gear.

Thanks for any help.

Hugh

trigger

A motion detector, like those used in home security systems seems like it would be ideal if you want to trigger it when somone walks by. Have this power a relay, which will act as a switch for the board. as for the switch, i think your probably right where the it is concerned. if you can get it to trigger with just a regular switch then this should work fine.

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