PIR Sensor Project

Other Hardware General Electronics
1

Hi all,

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).

To achieve this, I am planning on using multiple PIR (passive infrared sensor) chips. Like these - PIR Motion Sensor (JST) - SEN-13285 - SparkFun Electronics

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?

Thanks for your time and thoughts!

2

This was meant to post on the sensor area of the site. Lots of tabs open. My apologies.

3

Short range sensing might be better served by ultrasonic detectors - these are also
typically more directional and faster to respond.

4

Also with the ultrasonics you get an idea of distance, and can ignore anything further away than you want.

I do wonder how well they would work on soft clothing though.

5

Maybe a stupid idea, but could you mount the PIR detectors on the ceiling (facing downward)? That would presumably limit the range (depending on the height of the ceiling and the angle covered, of course).