[Jordan] managed to cobble together his own version of a low resolution digital camera using ... photodiode inside of a tube. The diode is connected to an analog input pin on an Arduino.

Researchers developed a single photodiode sensor that detects full-color light using perovskite materials, impedance data, ...

[td0g] created the light gates using pairs of infrared photodiodes and LEDs. When there is a sudden dip in the amount of light received by the photodiode, the Arduino control circuit knows that an ...