You can sense a lot of things with the right sensor ... The controlling chip — an Arduino, in this case — can read the intensity of the selected color. The TCS230 uses a 4 x 4 array of ...

It’s also a very handy thing to have when paragliding, which is why [mircemk] decided to build a hand-held version using the Arduino Nano and a BMP180 pressure sensor. Since you don’t want to ...