In a system for monitoring trash compactors, each monitoring unit associated with a trash compactor comprises a transducer for sensing hydraulic pressure, for generating an analog signal from the sensed pressure, and for converting the analog signal to a frequency signal, and a microprocessor. The microprocessor...http://www.google.fr/patents/US5303642?utm_source=gb-gplus-shareBrevet US5303642 - System for monitoring trash compactors
