Diagram for Reference

Everybody are making Arduino clones. So I thought I should make THE smallest. I took smallest package atmega88 – 28qfn (5mm x 5mm). Routed smallest possible resonator and as much pads as i could fit on in. The result – Smallest Arduino clone ever! Size is only 7.4mm x 7.4mm! Features include:

It needs arduino bootloader for atmega88 like ottantotto bootloader, probably it needs some hacking too because the resonator is 8MHz not the Arduino regular 16MHz. [Link]