I use this sparsely populated for low power applications and it works perfectly. I also use the same code on an UNO. They are interchangeable. I use the $1.60 Arduino chip, also sold on this site, the 16MHZ crystals(also on this site) with external 20pf caps mounted on the solder side. The cost is so low that I do not have to breakdown one project to build the next. I do drill mounting holes. One at R3 text (must repair the d8 track), the other very near ext text. Fun on the cheap.



