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NPN output sensor


Can anyone respond with the proper way to interface the following sensor output circuit with an EMX interrupt port?


Configure an input pin with a Pullup resistor type. Hook the output of the sensor (black wire) to the input. The sensors power supply must share a common ground with the FEZ power supply.


Thanks…the reason for the question is that I got a sensor labeled as NPN, but in fact I beleive its a PNP. I was questioning myself on how it should be hooked up when I tested the outputs. Glad I tested it before I hooked it up or the Cobra would have fried.



An NPN sensor pulls the output to ground when it triggers. A PNP does the opposite. Generally speaking NPN sensors a lot more flexible as you can power the sensor from a different voltage than the logic circuit it is hooked to.