Arduino

Arduino is an open-source electronics platform: it combines simple hardware (microcontrollers) and software (IDE) for building interactive digital devices.

Arduino is the premier open-source electronics prototyping platform: it makes physical computing accessible to everyone (artists, makers, engineers). The system centers on a programmable circuit board, like the popular Uno model, which typically features an 8-bit ATmega328P microcontroller, 14 digital I/O pins, and a 16MHz clock speed. Users write code (called 'sketches') in the C/C++-based Arduino IDE, then upload it via USB to the board. This allows the board to read inputs (sensors, buttons) and control outputs (LEDs, motors, displays), bridging the gap between the digital and physical worlds for countless projects since its 2005 launch.

https://www.arduino.cc