I'm working on a project to build a dance pad for video games. It needs four sensors, each one detecting whether or not an 11"x11" panel has someone standing on it. The end result will look similar to: http://www.angelfire.com/d20/ddrhomepad/ddrpad1.html , although I plan to implement it differently. Most similar projects (including the example above) work by sandwiching some non-conductive foam between two conductive panels, detecting when the two panels touch. For both durability and comfort, I want there to be no humanly-noticeable displacement when a panel is triggered. I'm having trouble finding a type of sensor that can accomplish this. Each sensor needs to be durable enough to survive being repeatedly stomped on while also being able to quickly (within ~1ms) detect contact or release. Each needs to be able to detect both sharp (milliseconds) and gradual (several seconds) contact and release. Each must detect contacts anywhere from a couple pounds of force up to hundreds. Each has to be able to work no matter what causes the contact, anything from an elbow to a heavy rubber boot. Each also needs to be able to detect prolonged contact anywhere from milliseconds to [at least] 20 seconds. All of this with a maximum low-volume cost of $2-5USD per sensor. Another requirement is that after initial testing, it shouldn't need any manual calibration. If it needs to self-calibrate, it should be able to do so upon power-up and then work properly for at least several hours without any user-visible calibration (for instance requiring the user to step off). The sensors don't need to determine how much force is being used, only whether contact is present. Ideally the sensors should be directly readable using a PIC with analog inputs and minimal external circuitry, but any reasonable amount of external circuitry would be fine. I have been looking at cheap piezo transducers, but I'm not convinced that they will be able to accurately detect gradual or prolonged contact. Reading a bit it appears to me that these are unreliable below 10 Hz, and I don't know if software tricks would be enough to compensate. I've also considered capacitance-based non-contact sensors, but I'm not sure these could detect contact from heavy rubber boots while avoiding false positives from bare feet just slightly above contact. The only sort of sensors I've seen that would seem to work are heavy-duty load sensors, in the neighborhood of $50-$500 each. The budget for the entire electronics portion of the project is $20-50, so these wouldn't do. Any advice is greatly appreciated. -Rick Luddy -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.