Here is an ultra simple Arduino Night Alarm project wired around a handful of inexpensive and easily available components. One advantage of using Arduino as a security system is the flexibility!

As photons (light) land on the detector, the resistance will decrease. The more light is we will have a lower resistance. By reading different values from the sensor, we can detect if is it light , ...

We know that measuring the speed of light with an Arduino is possible. It’s just that the implementation is hard. [Udo] hit upon the idea of pulsing a laser pointer and measuring the time of the ...