Hello world! Today i made an example on how to build a simple pir motion detector/alarm. I will build one that sends a sms on detection with a gsm shield later.
The motion detector simply reads high or low value. High on detection LOW on no Detection.
You can add anything to it to let the motion sensor trigger something.. such as switching on or off relays to turn on or off a device when motion is detected.
Follow the next step for the Schematic, Code & parts list.