If you’ve always wanted to try to build an Arduino project, this may be a great way to start. Matt Williamson built a tiny, Arduino-based motion sensor that will SMS you when something moves by your desk or into a room. It’s completely open source and the notifications system runs on your PC thanks to a simple Python script.
Why is this interesting? Well it only requires 67 lines of code to perform something quite useful and the hardware is very easy to build as it uses pre-made boards and a little plastic container to store the motion-sensing components. It’s no automatic robot lawnmower or AI-based hovercraft, but it’s still pretty cool.