Arduino is one of the most popular open source development boards that is used by DIYers and makers from all around the world to design and build new devices that talk to the real world.
From time to time tinkerers play with its design and prepare different types of development boards. AAduino is one such amazing creation, thanks to Johan Kanflo.

As the name suggests, this Arduino-compatible board is as small as an AA battery. “Powered by an ATMega328p, it is fitted with an RFM69C companion, two DS18B20 temperature sensors and an indicator LED,” its GitHub description says.

The AAduino is a wireless Arduino clone of the size of an AA battery with Keystone battery terminals rotated 180° to perform the work of a positive and negative terminal. This idea to connect AAduino to the batteries is something really intuitive and elegant.

Based on Tiny328, AAduino box (a three-AA battery holder) accommodates two AA batteries and an AAduino. This arrangement brings the awesomeness of this computing platform to the coolest form factor yet.

It runs at 8MHz to allow a greater life span since the CPU can run at a lower voltage. You can opt to run at 4MHz but it would drain batteries faster.

To accommodate the RFM69C in the case, Johan used a file to make it slightly narrower and similar to AA batteries. He also drilled a hole in the battery box to protrude the sensor and an LED to shine through.

If you are wondering to know more about AAduino and its details, head over to GitHub.