How to get the Arduino to close a circuit

Forum 2005-2010 (read only) General Frequently-Asked Questions
8

Both Radio Shack and Adafruit reference the Parallax datasheet so it's safe to assume they're all very similar.

This is how I got the Parallax module to work...

  • Connect Vdd to +5V
  • Connect Vss to GND
  • Connect OUT to one of the Arduino pins
  • Configure the Arduino pin as an input
  • Use digitalRead to read the PIR output. If digitalRead returns TRUE, motion is detected.

Bear in mind that PIR sensors have a warm-up time. You may be reading a "strange" output voltage because the PIR is warming-up.