We’ve seen [Johan]’s AA-battery-sized Arduino/battery crossover before, but soon (we hope!) there will be a new version with more MIPS in the same unique form factor! The original Aarduino ...

9V battery with dc High quality kit with UNO board, compatible with Arduino UNO R3, UNO R4, MEGA 2560 R3, NANO.

Aside from the USB port, you can power your Arduino boards with any regular battery connected to its ... sophisticated ...