Mindstorms Sensors

I am looking for ideas for new sensor types that people would like to be able to
attach to their RCXs.

I know mobile robots are the most popular building choice for Mindstorms, but
there have been some exceptional stationary models which may have applications
for specialized sensors.

Some choices for mobile robots would include devices like compasses to improve
the heading accuracy. (I have one or two compasses if anyone has a pressing need
to try one out.)

So please respond to this thread or feel free to email me directly if you have a
sensor idea to explore.

JB

ps: Has anyone has taken a look at the EyeC product from www.tern.com? I have
been wondering if this product might make a good robot sensor. I might be
interested in building an interface between it and the RCX (perhaps via IR LNP)
if anyone wants to give it a try.