What is in a Ba-zaar? A Model of Individual ParticiPation in an Open Source Community

A constant current generator supplies a constant current signal to a plurality of detectors and a reference resistance connected to an output line and a ground line. Each detector includes a reference resistor connected in series in the output line, and a sensor connected between the output and ground. Upon the incidence of an external stimulus, the sensor becomes conductive shunting out all resistance subsequent in circuit and causing a predictable voltage change at the output of the constant current generator. A trigger senses the voltage change and sends signals to cause operational signals to be sent as desired, for example, to shut down a personnel cable transport system (e.g., ski chair lift) and indicate the location of the external stimulus. A detector may be bypassed by placing a permanent magnet on or into its chassis. The constant current generator output is unaffected by changes in temperature.