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Shae Erisson's blog - Open Source Hardware Hearing Aid Part 1
My mother got hearing aids a few years ago. About a month later, she lost one. Insurance said if she wanted a replacement, she could pay them many thousands of dollars or she could wait a year.
That seemed incredibly expensive. I haven't done much electronics, but digital signal processing doesn't seem that expensive? I started diving in, the parts for a hearing aid looked like they couldn't possibly cost more than $500, probably closer to $100. A friend of mine was in a medical device software job, and told me human testing starts at about half a million dollars.
No way I can get that kind of money, so I gave up on that idea.
Years later, I found an affordable open source hearing aid
A few weeks ago, I found an open source hardware hearing aid called Tympan. For only three hundred dollars US you can buy a white 3D printed case that holds a Teensy 3.6 with some additional audio processing hardware. If you've previously done Arduino development, the Teensy is similar, and can use the same tools.
So I bought one!
(Score: 3, Interesting) by driverless on Monday August 05 2019, @10:29AM
My mother bought a multi-thousand-dollar hearing aid some time ago. They all cost multi-thousand dollars, it's not that she went for a particularly exotic one. She used it a few times and it's been in a drawer ever since because it enhances the wrong sounds (her words) and makes things worse than not using it at all. In any case her hearing wasn't that bad to begin with, I don't think she really needed it.
So definitely get the cheapest you can find, and on the remote chance that you do need a better one, get one of the pricey ones later. Most of the time though you'll find you don't need the pricey ones at all.
(Score: 1, Insightful) by Anonymous Coward on Monday August 05 2019, @12:52PM (2 children)
The cost of a hearing aid is partly marketing/regulatory and partly making it small/low battery drain.
This thing bypasses most of that, but given it goes in your pocket, how about a version that's just an app on the cell phone?
(Score: 1) by brkpt on Monday August 05 2019, @02:59PM
Google released their Sound Amplifier app to do just that a few months ago, I'm sure there are other apps available as well.
(Score: 2) by toddestan on Tuesday August 06 2019, @02:26AM
Another complicated part is the feedback canceller, which you'll need if you're putting the microphone and speaker right next to each other as with a hearing aid. With this device, with the microphone far away from the speaker in the ear, they don't have to worry about.
By the way, the iPhone has "Live Listen" built-in, which will let you stream the iPhone's microphone to some Bluetooth headsets, like Apple's own Airpods. It also works with hearing aids that are compatible with the iPhone.
(Score: 2) by Rich on Tuesday August 06 2019, @08:15AM
That "Tympan" is massive. Don't these guys have any pride? A very quick look over the net found the AK7756EN DSP from Asahi Kasei. Built in ADC and DAC, 3x3mm DFN, 47mW. Thank you AKM, for a decent datasheet. Then there's the Forte iM401, but I have the suspicion that this shop would first and foremost like to drain off some of the wealth from the hearing aid market rather than providing a well documented platform, so AKM get the design win.
The AK would run 7 hours at full speed from an AAA sized 10440 Li-Ion. Some power saving tricks might help, so we get to the good enough "day of power" and an in-or-on ear solution is feasible. I've never noted wired ear plugs to be really distracting, so an external power connector where the batteries go, or even stackable (plug-battery-aid) for recharging could be a good option.
Thinking of AirPods as benchmarks, ... why not hack them? If they can run a bluetooth codec, they can run an equalizer. Ok, even getting to the electronics inside can be hard, but it would be easier to fit a replacement for the cracked shell than re-engineering the contents from ground up. Might be a no-go though, if they have masked rom.
Finally, the "What's all that vocoder stuff about, anyhow?" analog solution: Take a look at the Polymoog Resonator, Korg VC-10 and Roland VP-330 schematics. 4 parametric, or 20 fixed band channels, or a combination of those two, might be a start. Doing the settings via OTAs on a 50uA bias current, with low power opamps, should make a total power budget of half the above DSP possible. But it would be a huge device, unless you get a specialty fab (e.g. Alfa RPAR) to integrate it.