RESNA 28th Annual Conference - Atlanta, Georgia
The diagram shows three electrode connections, two electrodes the input signals to an active electrode, the third electrode is a ground reference electrode. There are three analog to digital (a/d) converters shown on the diagram. One a/d digitizes the signal from the active electrode, the second a/d digitizes the signal from a front panel threshold adjustment potentiometer, and the third a/d digitizes the battery voltage. The digitized active electrode signal is passed through a digital filter. The output of the digital filter and the digitized threshold signal are input to activation logic. The activation logic drives a switch closure relay, and activation indicator, and an audible piezo transducer. The diagram also shows the power supply details, which include a wall transformer, a charger, a NiMH battery, a DC/DC converter. The digitized battery voltage is passed through a battery threshold logic block in the microprocessor. The output of the battery threshold block drives a battery indicator, and an audible piezo transducer.