It should be a piece of cake if you program your Attiny85 chip (not Digispark) using your existing Arduino IDE with the help of one “USB tiny ISP (v2.0)” programmer. The software/Arduino sketch /* * ...

PIR Pin “+” connects to Arduino +5. PIR Pin “-” connects to Arduino gnd. PIR Pin “out” connects to Arduino Digital 2. Here is the Arduino code for the Parallax sensor ...

When everything’s plugged in, this is how your Arduino, motion sensor, and power relay should look. Jeremy S. Cook Plug the male-to-female jumper wires into the motion sensor pins.