🚀 go-pugleaf

This may be a terribly basic question; if so, please forgive me - I'm pretty 
much a novice at this!

I want to build a circuit that senses the pressure someone's foot is exerting 
on a surface, without using springs, rheostats etc, because it has to be small
& simple. Is there such a thing as a small (e.g. < 0.5" tall) transducer or
some such component whose resistance/capacitance/whatever varies with the
pressure exerted on it? (The weight would range, I guess, from 0 up to ~ 200
pounds). Basically what the circuit is to do is this: there should be a
potentiometer or some way of adjusting a reference 'weight', and if the weight
on the transducer exceeds this reference, an LED should light up, or a buzzer
go off, or whatever. I can manage this part of the circuit, but any 
information/pointers regarding the existence of transducers (oh! and cheap
ones as well, if possible!) or else alternative ways to implement this, would
be much appreciated.

Thanks in advance
Patrick Edmond

pedmond@a.gp.cs.cmu.edu