Microcontroller demo boards such as the Arduino UNO are ubiquitous on Hackaday as ... and moved on to the power supply to make it self-sustaining, then onto the communication circuit, and finally ...

Read more: Battery Brands Ranked From Worst To Best The Arduino Uno ... jack or VIN pin. The GND pin, which you already know, is for grounding your circuit. The VRTC pin is meant to be a power ...