I have been trying to get Arduino to work with externally powered IR sensors for a while now with little results. Initially, I was using Arduino to rout the signal from the sensors to Max MSP, but now I need Arduino to read them. The model number of the sensor I'm using is SSR-0P-4E.
The problem is getting the sensor to communicate with the Arduino in a manner that is controllable. There is one "control" wire that connects directly to the Arduino digital "in" pin from the sensor. The Arduino code is told to read the sensor, and then print what it "sees" in an on/off fashion (0's and 1's). The Arduino reads that there is something connected to the pin by switching from all "0's" to displaying "1's" also, but there is an identifiable pattern to the numbers. A reading might look like: "1,1,1,1,1,1,0,0,0,0,0..." or "1,0,1,0..." both of which repeat. A voltage meter test revealed that there was 1.489 Volts passing through the "control" wire to the digital input pin. Is this a problem of not enough voltage being sent to the pin to read it, or the way Arduino is reading the incoming voltage/sensor control message? I found that Arduino registers as "HIGH" when a pin reads more than 2.5V and "LOW" when the voltage is less. Is this a power supply issue since I have to use external power for the sensors (their operating voltage is between 10 - 30VDC)? I'm using a 12VDC wall wart. Any help would be much appreciated.