Friday, March 3, 2017

Unifying the Electronics to Make "Tympan"

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!
As you can see, it's a lot smaller than my breadboard system.  Most importantly, there are no loose wires flying around to get caught on things or to pick up noise.  It's much more robust, thereby enabling you to be mobile.  And being mobile is the best way to trying out your new audio processing algorithms.   Being mobile is where things get fun.

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.
When our new board is combined with the built-in capabilities of the Teensy, you've got a nice and compact little system for developing new audio processing algorithms.  It's got a lot of really useful features!
Now that I've got this cool little piece of hardware, I've got some colleagues who are going to start working with it, too.  As more folks work with it, we figured that it needed a name.  After trying out a bunch of names on friends, colleagues, and in the open-source community (and seeing what was available for handles at sites like GitHub), we chose the name 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, we've put them on Tympan's GitHub.  The original "Rev A" design is here.  The first hardware that is for sale ("Rev C") is 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.


  1. The link to the tympan github is broken

    1. Hey, thanks for letting me know. I've fixed the link!


  2. How do I use the Bluetooth connectivity