I recently had to build an infrared close proximity sensor that could tell if something was dropped in a parcel delivery drop box. After some searching, I ended up using a microcontroller ... Here is ...

The hardware is consists of an Arduino microcontroller ... dry conditions using just two LEDs (green & red). int GLED= 13; // Wet Indicator at Digital PIN D13 int RLED= 12; // Dry Indicator at Digital ...

Arduino’s brand-new Esplora microcontroller ... “So, something you could just plug in and use right away.” These built-in sensors separate the Esplora, which is based on the Arduino ...