I'm starting a new project and I'm looking for any heads ups, or advice on the following as I haven't worked with motion sensors before. But I have worked with touch and proximity.
It's an immersive theatre piece/walkthrough installation. The piece is made up of different 'areas.' Each area, has it's own soundscape/audio. Audience members will be wearing wireless headphones, receiving audio from a wireless transmitter, which will be receiving audio from Max/MSP.
Throughout the installation, I plan to use motion sensors, to detect when audience members (no more than 2 at any given time) enter into an area (thus activating the audio for that particular area).
Using an Arduino Mega / Duemilanove, I plan to wire these sensors from the board to each of the entrance points in the various areas.
My real question at the moment is regarding the sensors, can anyone give me advice on the PIR sensors? Their field of detection is quiet wide (up to 20ft). I need something that will only pick up roughly a metre squared around itself. Anythnig more than this would be a nightmare. So I think, perhaps these are not the best choice for this project? Or is it possible to work this into the code, like you can lower the sensitivity of the prox sensors in code, for example?
Perhaps you could use ultrasonic distance sensors (e.g. HC-SR04)? The have a much narrower "beam", and they give you relatively accurate distance reading so you can decide in code what your threshold is.
Do you have any input on this? Essentially I only need to monitor / take input from a very small, enclosed area. Anything beyond this will be counter productive!
No, this kind of Line Sensor's range is way too short - at best, you could probably squeeze a reliable 1cm out of it.
There IS another class of IR proximity sensors for longer ranges, by Sharp (see for example https://www.sparkfun.com/products/242). They may do the trick but are more expensive than the Ultrasonic and I see no particular advantage in them for your purpose.