Meet Tympan, The Open Hardware Hearing Aid

If you’re the kind of person who’s serious about using open source software and hardware, relying on a medical device like a pacemaker or an insulin pump can be a particular insult. You wouldn’t trust the technology with your email, and yet you’re forced to put your life into the hands of a device you can’t examine yourself. Unfortunately we don’t (yet) have any news to report on open source pacemakers, but at least now there’s an open software and hardware hearing aid for those who need it.

The Tympan project aims to develop a fully open source hearing aid that you can not only build yourself, but expand and modify to fit your exact specifications. Ever wanted to write code for your hearing aid with the Arduino IDE? No problem. You want Bluetooth, I2C, and SPI? You got it. In truth we’re not sure what this kind of technology makes possible just yet, but the point is that now those who want to hack their hearing aids have a choice in the matter. We have no doubt the community will come up with incredible applications that we can’t even begin to imagine.

But these open hearing aids aren’t just hackable, they’re affordable. Traditional hearing aids can cost thousands of dollars, but you can buy the Tympan right now for $250. You don’t even need to check with your health insurance first. Such a huge reduction in price means there’s a market for these outside the hardware hacking crowd, and yet another example of how open source can put cutting edge technology into the hands of those who would otherwise have to go without.

The latest version of the Tympan hardware, revision D, is powered by the Teensy 3.6 and features a Sierra Wireless BC127 Bluetooth radio, dual MEMS microphones, and even a microSD slot for recording audio or logging data. It might be a bit bigger than the traditional hearing aids you’re used to seeing, but with an external microphone and headphone setup, the wearer could simply keep it in their pocket.

We’ve seen DIY hearing aids before, but unless you’re willing to carry a breadboard around with you, they’ve generally been limited to proof of concept sort of builds. We’re glad to see a mature project like Tympan join the growing movement for open source medical hardware; it’s a another big step forward towards democratizing these critical pieces of technology.

34 thoughts on “Meet Tympan, The Open Hardware Hearing Aid

  1. In many jurisdictions it would be illegal to call this a hearing aid, since that is reserved for medical devices that conform to relevant standards and processes. It could be called a personal sound amplifier product, or similar.

    BTW the ear-brain combination is extremely non-linear, and everybody’s hearing loss is different. Very careful measurements and fitting and post-fitting calibration of the device in the canal is required.

    Yes, I do have personal experience, and there’s no way I would trust an amateur effort, no matter how well intentioned. Neither would I trust shop technicians paid on a per-sale basis!

    1. “Neither would I trust shop technicians paid on a per-sale basis!”
      *Blinking in disbelief* You mean like the Hearing Instrument Specialists who while state licensed are not doctors and are not bound by legal ethical requirements to act in your best interest and thus can legally ignore the presence of cheaper models and push people to the most expensive piece of equipment their insurance will bear? The folks who sell bespoke in canal devices that cannot be returned due to their custom nature? Like those people?

      1. Where I live, everybody is entitled to free hearing aids, so there is no financial incentive to affect their choice.

        My family has experience over the decades since the early 50s. There have been many people touting very expensive hearing aids that (after you have bought and paid for them) turn out to be no better (or even worse) than the freely available ones. Hearing aids are easily lost or damaged (e.g. by water or macaws), and are not especially reliable – and need to be replaced regularly.

        I feel sorry for people that have to pay salesman for their hearing aids.

        For the avoidance of doubt, my family has reqired aids to help with losses up to 95dB, i.e. including high-end specialist devices not only run-of-the-mill devices.

        1. Where I live hearing aids are also free which means you need to have a mandatory medical “insurance” which cost like 120 euro minimum a month and you have an income tax of 40-55% depending on your income.
          In fact we all pay a premium for these “free” devices even if you never need one.

          Al the devices I have seen till now are simple dsp audio processors that can be programmed, no custom stuff at all.
          Shouldn’t cost more than 300 euro max but goes for 1000-3000.
          Go to a medical doctor to measure your hearing and after that buy the open source one as a ,atter of principle

        2. “Where I live, everybody is entitled to free hearing aids, so there is no financial incentive to affect their choice.”

          1. There is no such thing as FREE! If you didn’t pay for it, somebody else did – until all those people being forced to pay for your FREE stuff just leave. In the end, FREE stops for 99.9% the people, and the 0.1% who run the Government get rich. I suggest you take a nice vacation to Venezuela (just one example of many) – and ponder this.

          2. With NO financial incentive to drive innovation and competition, you end up with NO CHOICE! In your “ideal” world, everyone that needs a hearing aid would be carrying around identical backpack sized devices with huge batteries and vacuum tubes .

        3. “Where I live, everybody is entitled to free hearing aids”
          Not all of us can live in Asgard. I live in BadHombreLand and to get a “free” hearing aid, you have to file a ton of papers for approval that almost always get lost in bureaucracy. Or, if you work in a government office like yours truly, you file a ton and a half of papers to prove you really need it, then another mountain for approval, just to get rejected because the (very few) available free units were given to the highest rank bosses who could easily buy them with their outrageously-high wages.
          You feel sorry for people that have to pay salesmen for their hearing aids. I feel sorry for you that will never feel the need for or support innovation.

  2. Unfortunately, by calling anything a “hearing aid” you incur regulatory barriers in many countries.
    My grandad was a soldier, and like many others had more severe damage to his hearing on one side.
    I had always thought a directional-microphone that could suppress background-noise would be a notable improvement. Additionally, a broadcasting trick used in Radio which can be tuned for a specific users range may prove useful for speech perception in noisy environments.
    https://en.wikipedia.org/wiki/Dynamic_range_compression

    Keep in mind it is often socially awkward for these folks, and most will not readily admit they are having equipment issues unless asked in an appropriate setting. ;-)

    Great project.

    1. Noise reduction and frequency-dependent compression are standard on modern aids. And each ear’s characteristics are different and vary over time.

      If you have to use hearing aids you will also find that you need different characteristics in different environments, e.g. relating to wind, tyre noise, music, crowded rooms, and more

  3. I have an old button tied to a string. I slip the button in my ear and the end of the string in my pocket. Everybody see this “device” and just talks “louder” around me. problem solved. Cost: $FREE

  4. I’ve looked into hearing aids before, and honestly, out of all the electronics out there, I think it’s literally the most difficult piece of commercial electronics to make as an individual. It’s in a completely different league that glucose sensors or many other medical devices, where honestly any decent EE could probably do something similar with something off the shelf. There’s quite a bit of processing that needs to be done, it has to fit in a really tiny package, and be extremely power efficient so that it can run on a single 1.5V (high power) coin cell battery. Most designs use at least semi-custom ASICs with special DSPs that operate directly on < 1.5V, with no DC-DC converter (for size and power efficiency!) IMO nearly impossible to touch that level of performance without custom ICs. I have a lot of respect for these designs.

      1. But it have a processor powerful enough to do DSP. DSP = application optimized processor, nothing more.
        Note the size difference though – this is much larger than the extremely power optimized DSPs of real hearing aids.

    1. Fully agree with you regarding efficiency of the custom ICs/Hybrids. These puppies are massively efficient. I just recently built such a device for a customer powered by a tiny 23mAh NiMH cell. I decided to do a test to see how long the cell would last if the system was oscillating continuously at max volume. It was loud enough that you could hear it from 2m away and the darn thing ran for 23hrs!!!

    2. That’s pretty much the case.

      Especially when you try to get them to run on one pill-sized zinc-air cell. Why zinc-air? Because the air “electrolyte” is very lightweight, and that matters.

      I believe, but have not verified, that the manufacturers use old (large geometry) semiconductor processes with special doping profiles (to get the low power and low voltage operation).

  5. No doubt a handful these days gets you more tech than a handful did decades ago, but this is still quite handful. For those in deep poverty $250 is a fortune, so I can’t see this only sought by the truly desperate.Even one quanta to try to modify an ultra miniature latest tech hearing aid, doesn’t mean they need to do so, or they are capable of improving them.

    1. In the U.S., a single ‘approved’ hearing aid is priced between $1500 and $4000, so 250 USD is an order of magnitude improvement.

      And many commercial hearing aids simply do not do anything to improve quality of hearing. A commercial hearing aid that does not work can sometimes be returned but cannot be hacked. This thing can be continually re-programmed and re-configured to incrementally improve.

      1. The price and comments about quality of commercially fitted hearing aids is true where I live. The majority of the cost is not in the aid itself, but in the support service/equipment required to measure the hearing loss and post installation tweaking.

        Hence my earlier comment about being very grateful that I live somewhere where hearing aids are free and there are no commercial charlatans/imperatives.

  6. You can get fitted at an ear specialist for protection plugs or for in ear monitors. This much cheaper, then drill holes. Then hook up whatever. I have a notch at about 2-3k, but it’s not about just tuning up a band as loudness still causes more hearing loss. Careful compression and noise gating in particular bands, and a whole lot more.

    In high school i had a friend that had some nerve hearing loss. I had a portable stereo cassette recorder with a 90 degree spaced pair of mics on the headband of the headphones. With the gear on he could hear the birds in stereo.

  7. Just as the ubiquitous presence of smart phones has removed the stigma of conversing with an invisible other on the street, a cell-phone lookalike which acts as a hearing ‘enhancer’ via bluetooth earbuds would not excite any comment. Leave it on a restaurant table, no problem. Put it in your shirt pocket or hold it in your hand? No problem. The battery could last many days and be rechargeable. You wouldn’t need to cram processing, DSP and other features into a 2-3cc container. I think this project is an interesting, useful starting point.

    A further enhancement would be building hearing enhancement into an actual cell phone. I suspect that feature is not far away, given the aging population in the US.

  8. Instead of using this as a hearing aid but as a high fidelity hearing protection that does not attenuate the music in such a way to distort so much as some other hearing protection does. This will be not easy to implement as too much delay will be immediately noticeable, but this seems like a suitable platform to at least do some tests.

  9. I hope version 2.0 has a directional microphone array. directional sense and picking one voice out of a crowd is something else that’s often lost with hearing aids. Adding that back in would help a lot.

  10. It´s missing a T-coil. Induction loop systems that are set up correctly are a wonderful help for people with hearing aids specially in places with poor acoustics or loud background noises.

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