Help w/3 ft distance configurable proximity sensor

Hi Folks,

I'm hoping you can help me brainstorm a way to meet my requirement. I'm working on an art project where I want Arduino based exhibits to interact w/ each other based on how close they are to each other.

In an ideal world, the arduinos would be able to recognize each other and know when they're close enough to interact.

My first thought was to send patterns w/ IR light but that won't work because it will mess up digital cameras.

Thanks!

Jonathan

I should add my installations will have XBee radios on them already. In a perfect world, I'd be able to read the signal strength on a per packet basis. I haven't found an Arduino API yet that lets me do this, anyone have any experience?

Thanks!

Jonathan

Maybe you could use ultrasonic sensors and have all the arduinos calibrate themselves at startup so they send the ping at different intervals, but how would they move? Because if you use the ultrasonics, I believe they would have to be directly facing each other all the time.

Just an idea.