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. ... (Arduino Uno/Nano Sketch)… [code] ...

Note: A compact analogue reflectance sensor such as the CNY70 was not used in the Arduino Uno experiments described. Instead, a homemade sensor was assembled using a single infrared LED (IR333C) and a ...

If you have an Arduino that can act as a keyboard for a PC, the code almost writes itself. ... The serial communications is I2C and there’s a tiny optical sensor onboard along with an IR LED.