After having lots of fun with the breadboard version of my Teensy Hearing Aid, I decided that it was much too bulky and fragile to be of much use. So, with some help, we designed and built or own custom audio interface for the Teensy 3.6. This new audio interface would take all of the elements of my breadboard system and bring them together into one unified board. Stick a Teensy 3.6 on top and it's good to go!
On of my favorite features is that the board has two tiny little microphones built into the board itself. So, for quick trials, all you need to do is plug in some headphones and you're ready-to-go. I even put a hole in the PCB so that you can clip in a lanyard thing and wear it around the neck. Sure, it's pretty nerdy to have raw, unenclosed electronics dangling around one's neck but, hey, I'm not afraid to show my geek pride.
Tympan. As an open-source hearing aid device, that name seems pretty decent to me!
Follow-Up: If you're interested in the schematic and BOM, they're on the Tympan GitHub here.
Follow-Up: I measured the self-noise and dynamic range of the Tympan board. It's pretty good! You can check it out here.
Follow-Up: We designed an enclosure for the Tympan. You can check it out here.