Is there going to be another run of the Rev E hardware or maybe someone has one available?
A quick read of the Tympan Library README.md indicates it needs a Tympan Audio board, is there an off the shelf alternative that can be used to get started?
– wink
@winksaville, thank you for your interest. I’ll let @biomurph answer your question regarding the next production run. In the meantime, I have a Tympan Rev D that you are welcome to have for free. Just send me a shipping label. If interested PM me.
The Rev-D is based on the Teensy 3.6 while the Rev-E is based on the faster Teensy 4.1. The former is still quite capable though.
To clarify, the Tympan is a Teensy board with an integrated audio codec. It does not need an additional audio board. The code features multiple inputs and outputs, but only processes (2) channel audio. If you want (4) channel audio, you would need to buy the Tympan Audio board.
Hi @winksaville
We don’t currently have plans to produce more of the Tympan Rev E. There was some thought to making a Tympan Rev F (integrating the Teensy hardware with the rest of the PCB design, as we did with the Tympan D), but the funding for that is dear.
I currently have inventory of the AIC shield. This could be mated to a Teensy 4.1, but requires a simple PCB interface. That has yet to be designed.
PJRC sells their own Audio Board for Teensy, but it uses a different codec and will not work with our library, I don’t think.
Eric, I’d like to take you up on your offer of the Rev D board, but I couldn’t PM you, if the offer is still open you can contact me at wink at saville.com.
– Wink
I’ve no capability of creating hardware, I’m a software type 
What type of funding would it take to for a Tympan Rev F? And what needs to be done to create the PCB interface for the AIC?
Finally, somewhat more to my capabilities, what would it take to change the software to work with an existing tweensy audio board https://www.google.com/search?q=tweensy+audio+boards there seem to be quite a few.
Is there a documented “HAL” interface for the audio subsystem in the library?
Could you recommend a couple that you feel would be suitable for creating a simple readily available “development” system?
– Wink
Making Tympan Rev F: There has already been successful design work that incorporates the Teensy 4.1 essential components with the same audio CODEC that the Rev E uses. That does make it a bit ‘easier’, but there is still a lift involved in completing a PCB design that will work in the Tympan ecosystem (AIC Shield, Earpiece Shield). The practice we have been using is to create a small number of prototypes (4-6) for testing and then if there are design changes we make them prior to a larger run (10). That amount of design and production work runs roughly $20K. The next step would be to leverage mass production to bring the per unit cost down to a reasonable and affordable level for online sales. Also an enclosure design needs to be made. Also batteries need to be acquired. Also any accessories, like belt clip, USB cable. One of the issues in all of this is that Tympan sales over time are rather anemic, and it is not showing itself to be a super duper sustaining commercial project.
Making Tympan Rev E: This is easier and cheaper, since the work is already done. The design files and BOM are on github, and also on Circuit Hub, which is a US based manufacturer that I used to make the Rev E. Here’s a link to the Rev E pages CircuitHub
Pricing for 5 units would be about $300 each. Pricing for 50 would be about half of that.
There is some additional work to be done after the boards are made and populated, that would be to attach the Teensy 4.1. The enclosure is already designed for 3D printing, so that is also nice.
Making Tympan Rev D: This is possible, but the Rev E is faster. The files for the Rev D are also on github as well as Circuit Hub.
CircuitHub
One major issue is that the bluetooth module that we are using has gone End Of Life. If bluetooth interface and/or bluetooth audio is desired, a new module would need to be sourced, and a new code base for interfacing with it would need to be built. That is not trivial.
@winksaville what is your application for the Tympan audio hardware?
Txs for the info, @erk1313 is sending me a Rev D and that sounds like the best starting point for now. Obviously a Rev E would be better, but that’s not in the cards
My interest is that I’m a retired programmer, 73yo, and my hearing has degraded enough that my wife insists I need hearing aids and the doctor says it wouldn’t hurt. I’ve resisted because the one time I tried them they were uncomfortable and my hearing isn’t that bad, so the patient says.
Anyway, as a programmer with some expertise in embedded systems I thought I’d like to explore what I can personally do. I’ve always had an interest in audio processing but I’ve never done anything in the space. So now is the time!
I know nearly nothing about signal processing, but what little understanding I have I’m assuming to make a “good” hearing aid you need to filter out extraneous low and high frequencies and then manipulate other frequencies to overcome the hearing loss of the individual. Furthermore the users needs will differ based on the environment as well as the current real-time desires/requirements. Obviously this isn’t a trivial problem, which makes it all the more interesting!
It’s also my understanding that the job of a hearing aid is to change the frequency response of the incoming signal and send the result to speakers. A search for audio dsp coretex-m7 seems to say the M7 is a decent choice, but I’m wondering if there might be newer processors (RSIC-V + DSP) that might be superior (more efficient, cheaper …).
Thoughts?
– Wink
Sounds like a great project. The Tympan Rev-D is still pretty capable, and should allow you to use 2 or 3 frequency bands. Since the libraries are virtually the same, when a Tympan Rev-E becomes available (or you decide to roll your own board based on Biomurph’s open gerber files) it is an easy upgrade.
Take a look at some of the examples, which use the on board DSP. There are a lot of things baked in that you can experiment with. For example here is a full multiband processor that provides compression.
Here is a simple app to show how gain of a band is controlled by input amplitude. Essentially you are trying to compress the full range of sound pressure into a smaller audible range.
https://tympan.github.io/Tympan_Library/WDRC_Plotter.html
From there you can explore beam forming… the use of multiple microphones that allow you to emphasize sounds in front of you, compared to omni directional.
Also there is frequency shifting… In some severe cases, you may want to shift the frequency band to regions the patient can hear easier.
A good tutorial on processing would be to check out the IIR and FIR filter types explored in the examples:
You can also explore how hearing aids are evaluated. Check out the manual for the Verifit 2. It shows how hearing thresholds are translated into settings for the hearing device.
At some point, you’ll want to move beyond commercial earplugs and microphones. If you feel like you are making progress with the Tympan, reach out to inquire about the custom earpieces. They have two digital microphones and a receiver in canal (RIC) speaker. They are hardwired to the Tympan (to prevent delay).
When, will the Typan Earpice be available again?
Just throwing out possible resources you might be interested in. Here is an online site for training audiologists: Audiology CEUs | All Courses | AudiologyOnline
I believe there are some free seminars in there.
Looking at the Rev D getting started guide it looks like the only hardware I need is headphone and microphone with 1/8" stereo plugs. Is there a “special” combination of headphone with stereo mics that might be useful? If not what would be recommended for input microphone(s)?
@winksaville
Some good news!
It turns out the bluetooth module is available, at least for a little while.
Also, I just sent out a quote for a short run of Tympan Rev E, which will allow me to produce a few extra for sale to folks like you.
The lead time on having units in stock is probably 60 days or so. 90 max.
Would you be interested in purchasing one?
Definitely want a Rev E, how can I reserve one and will it come with the Bluetooth module?
@winksaville
You just reserved one!
Seriously, there is a ‘back in stock’ notification button at the top of the product page.
Sign up for that and when the Rev E is ready to ship you will get an email notification.
Great, I’ve subscribed!
Hello all, I already had a Rev D but it quit working. Would like to buy rev E to start a class and educate young enthusiasts (10 pieces minimum). When should I expect to have them available for purchase?
Best,
S.