Step 4: Testing your PIR
Once you have your PIR wired up its a good idea to do a simple test to verify that it works the way you expect. This test is also good for range testing. Simply connect 3-4 alkaline batteries (make sure you have more than 3.5VDC out but less than 6V by checking with your multimeter!) and connect ground to the - pin on your PIR. Power goes to the + pin. Then connect a basic red LED (red LEDs have lower forward voltages than green or blue so they work better with only the 3.3v output) and a 220 ohm resistor (any value from 100 ohm to 1.0K ohm will do fine) to the out pin as shown. Of course, the LED and resistor can swap locations as long as the LED is oriented connection and connects between out and ground
Now when the PIR detects motion, the output pin will go "high" to 3.3V and light up the LED!
Once you have the breadboard wired up, insert batteries and wait 30-60 seconds for the PIR to 'stabilize'. During that time the LED may blink a little. Wait until the LED is off and then move around in front of it, waving a hand, etc, to see the LED light up!