I’m working on my first Max/MSP project for a sound art installation, and so far everything is going great. For one portion of the patch, I would like to have PIR sensors dictate the frequency of some recordings, but I’m not getting any variable numbers from the sensor. Does any one know if the PIR sensors are able to output variable data, or just high and low?
Most PIR sensors are wired up as logical motion detectors (on/off) for ease of use. Think of those porch lights that turn on automatically when people walk by. I think it’s possible to get analog data from a PIR, but it would probably require quite a bit of op-amp fiddling to get something usable. AFAIK, there is no easy out-of-the-box PIR analog sensor that gives usable voltages(although the PIR itself is an analog sensor).
You might be happier with an infrared ranger, an ultrasonic ranger, or camera detection.
I’ve used it, and you can get a general idea of direction of motion, sometimes, but it is very twitchy. It’s more accurate, but less sensitive, without the lens. There’s a great information resource here: