An inexpensive programmable stimulator for the study of thermal sensation

This report describes a simple thermal stimulator that uses a single-layer Peltier device to produce heating or cooling of the skin in the range 0-50 degrees C. The output temperature of the stimulator is determined by an external command voltage. The device incorporates a precision thermometer, and a novel feedback controller which employs out of phase gains to minimize oscillation of the stimulus temperature about the command value. Command waveforms are followed to within 0.05 degrees C for rates of up to 2 degrees C/s.