You youngins probably don’t remember this, but a few years ago there was an arms race on Kickstarter to create the smallest Arduino-compatible microcontroller board. Since then, a few people have realized they can make more money on Kickstarter through fraud or potato salad, and the race to create the smallest ‘duino board petered out.

It’s a shame [Meizhu] wasn’t part of the great miniature Arduinofication of Kickstarter, because this project would have won. It’s an Atmel ATtiny85, with USB port, resistors, diodes, reset button, LED, and pin headers, that is just 72 mils larger than the PDIP package of the ‘tiny85. Outside of getting a bare die of ‘tiny85s, there isn’t much of a chance of this board becoming any smaller.

[Meizhu] was inspired to create this board from [Tim]‘s Nanite 85, which up until a few days ago was the current champion of micro microcontroller boards. With a bit of work in KiCAD, the new board layout was created that is just a hair larger than the 0.4″ x 0.4″ footprint of the PDIP ATtiny85. There were a few challenges in getting a working board this small; you’d be surprised how large the plastic bits around pin headers are, but with some very crafty soldering, [Meizhu] was able to get it to work.

“Possibly the smallest ATtiny85 based ‘duino derivative”. Indeed! When Olimex announced the Olimexino 85s as the smallest Arduino ever, [Tim] took that as a challenge. His very small Arduino based USB devboard is quite a bit smaller than the Olimexino!

The Nanite 85 was carefully designed to be both small and functional. Not only is it 20% smaller than the Olimexino, but also sports a reset button! One of the coolest aspects of this design is that it has the same pinout and size as a DIP ATtiny85. This means that you can use the Nanite 85 for developing your code with the USB bootloader, and then you can directly replace it with a standard (pre-programmed) ATtiny85. The major downside to using this device over the aforementioned devices, is that it does not include a voltage regulator for powering the device via USB (or battery), the device is simply hooked directly to the 5V rail from the USB connector.

We can’t help but be impressed with this well-thought-out design. It is also easy to assemble since it uses larger surface mount components. If smaller components were used, even more features (such as a regulator) could be included. Do you have an even smaller USB Arduino? The race is on for the smallest Arduino ever!