AVR Programmer Transformed Into USB MIDI Adapter

As spotted on Reddit, Robson Couto was in need of a USB to MIDI adapter, and decided to pursue the “easiest USB MIDI implementation [he] could build in an afternoon.” Fortunately, Yoshitaka Kuwata had a similar idea, and Couto decided to modify his implementation to run on a USBasp AVR programmer, normally used to program AVR microcontrollers found on many Arduino boards. Since they are small and only cost a couple bucks, Couto keeps several on-hand.

For his adapter implementation, code (available here) was burned into the designated programmer using another USBasp module. The MIDI cable is hooked up to the programmer via a simple custom board and header, with a 6N138 opto-isolator separating the USBasp and MIDI signals. The boards use header pins for attachment, so if for some reason it needs to be converted back to a programmer, it should be a matter of unplugging and reprogramming.

This isn’t Couto’s first foray into re-purposing these programmers; he was actually able to use one of these as a Super Nintendo controller interface with another custom adapter in a previous project. While these devices certainly work well for programming chips as intended, perhaps it’s worth having a few around for custom USB adapter projects as well!

AVR Programmer Transformed Into USB MIDI Adapter was originally published in Hackster Blog on Medium, where people are continuing the conversation by highlighting and responding to this story.

Original article: AVR Programmer Transformed Into USB MIDI Adapter
Author: Jeremy S. Cook