Back to Black
LXF: How did the project evolve with the shift to an Arm SOC? co: The device consists of a Beaglebone Black small board computer, with a custom circuit board called the Cape4all which sits on top [much like a Raspberry Pi HAT]. This is an open hardware bit of kit that’s got three audio codecs on it, which enables six mono inputs and four mono outputs to connect to the Beaglebone Black.
This was developed by the university, but they had a lot of trouble getting the driver running. They managed to get one out of three codecs working, but they had a lot of difficulty with the others. At that point they asked for some external help, and they got in contact with us. Really the rest is just history. It started off with a fairly standard “Can you write us a driver?” request, and that was where we thought it would end. But we ended up getting quite involved with the project, and we actually developed a custom Linux distribution running a real-time kernel on the Beaglebone, with a bunch of features to help their research work.
The kernel includes some scripts which tweak all the drivers to run at their best real-time performance. We also include a Bluetooth LE client to allow communication with a mobile phone, so you can use an Android or IOS device to tweak parameters within the MHA software.
The idea is that end users can tweak settings. Everyone’s hearing loss
(pardon?–ed) is different, so there’s this ‘fitting’ process, where you go to an audiologist and they figure out where your lack of frequency response is so they can then adjust for it.