Hearing Aid Amplifier (II) - Page 1
Forum section: electronics / projects

author: WonderWheeler
author_rank: Contributor
timestamp: November 23, 2018, 07:21:51 am
content: This is a continuation of a conversation from January 2017 to some extent.I'm about to order the parts for a hearing aid that is Raspberry Pi based. Its developed by a German College of some kind and is open source.Documentation:https://github.com/m-r-s/hearingaid-prototypeFits in a belt bag, uses combo stereo headphone/microphones, and a bunch of stuff that fits in a fanny pack. So it looks a bit like a person listening to an mp3 player with ear buds. Cost of the materials is about 250 usd. A little complicated but it might be doable. Wish us luck lol.Planning on using the Raspberry Pi 3B+, a couple little preamps in a separate case with a 9v battery and some plugs. Also a audioinjector Stereo Sound Card for the Pi, battery pack, sd card etc. The software is open source too.Announcement from Raspberry Pi forum:https://www.raspberrypi.org/forums/viewtopic.php?t=199890

author: SiliconWizard
author_rank: Super Contributor
timestamp: November 23, 2018, 06:23:59 pm
content: This is a nice project and initiative.That said, unfortunately in terms of overall size, weight and power draw, this is going to be much like the first portable hearing aids from the 50's.Another thing that comes to mind is that using conventional earbuds will allow to help only moderate hearing deficiencies.Would be interesting to turn the idea into an open source, miniaturized hearing aid able to drive true hearing aid domes, although obviously that would lead to a completely different territory.

author: jeroen79
author_rank: Frequent Contributor
timestamp: November 23, 2018, 08:23:13 pm
content: Why would a hearing aid need a raspberry pi?

author: LeoTech
author_rank: Regular Contributor
timestamp: November 23, 2018, 09:47:47 pm
content: Quote from: jeroen79 on November 23, 2018, 08:23:13 pmI'm with jeroen on this one, it seems quite impracticable to base something like this on a Raspberry Pi, considering that in the end it is pure analog.And even if some digital processing was needed, why not offload it to a microcontroller or something smaller than a Pi, to make it both smaller, more portable, while increasing battery live.Or is there some major point we (I am) are missing here? (Just curious)Leo

author: WonderWheeler
author_rank: Contributor
timestamp: November 24, 2018, 04:30:30 am
content: Well, I guess I was hoping to also install an MP3 player also, and who knows what else. Yes, the computer does compress the signal to prevent overloading the eardrum, as well as perhaps some noise cancelling and boosting the high part of the frequency spectrum, where most of my hearing loss is.I'm more concerned about saving money than the fact that it might take up extra space. I am considering also having a POE hat so that at work I could power it off an ethernet line, although that limits portability of course.Edit: Also the ability to listen to music over the internet would be a plus. And since more compact in the ear hearing aids can cost 1000usd or more each and I don't have insurance that would cover it.Also of course, the opportunity to listen to loud rock and roll music to further destroy my hearing... lolUsing the latest Raspberry Pi may limit the battery life, but that is a calculated risk. We'll see how it goes!

author: WonderWheeler
author_rank: Contributor
timestamp: November 25, 2018, 08:04:38 am
content: Only holdup so far is getting the two preamp kits from Germany. They are not open on weekends, and I can't figure out how to get them shipped to the U.S. yet. Their automated system only allows shipping to European Union countries it seems.https://www.elv.de/smd-mikrofonvorverstaerker-komplettbausatz.html(in german)Its a kit and they recommend substituting the OpAmps with a different unit also. This will be my first experience with surface mounted devices.The INTENT of this design is to use off the shelf consumer stuff where possible. This is the most difficult part.Edit: This project can also be called "Hear What You Like To Hear", and I just found a YT lecture video:for those that are interested.

author: Twoflower
author_rank: Frequent Contributor
timestamp: November 25, 2018, 09:52:58 am
content: With hearing aid + RasPi I just remembered a cartoon from a German computer newspaper:https://www.heise.de/ct/ausgabe/2018-9-Schlagseite-4014353.htmlThe old lady says something along:"You know whatNerdmeans? That's a grandson who is building a hearing aid with RasPis and make them a Christmas gift"But more serious: For example look at the 'The Dash' in ear buds. They have a mp3 player, a hands-free function (with even multiple microphones) and many other stuff build in that would also do nicely as a hearing aid. Of course not open-source. But you might look how they did this and learn from it.How about an alternative to that Mikrofonvorverstärker and directly use a MEMS microphone (just as an example):https://learn.sparkfun.com/tutorials/mems-microphone-hookup-guide/allIt's smaller and obviously also available.As processing unit maybe an ESP32 might be powerful enough, much smaller and probably less power hungry.

author: mrs
author_rank: Newbie
timestamp: November 25, 2018, 04:58:06 pm
content: Hi there,I am responsible for the referenced GitHub project. Just to clarify...We are researchers and with this project I provide easy access to our research tools for a wider "audience" (open science). The core is the openMHA.org software platform which we use for our research.To be very clear: The mobile hearing aid prototype is a research tool, it is no product.We base it on the Raspberry Pi because there we have almost the computational power and flexibility as on our PCs, including running Matlab script with GNU/Octave. And many researchers work with Matlab. Hence, this allows us to test new approaches rapidly in real environments.I would encourage any technically skilled person (engineers, physicists, mathematicians, ...) to play with our toy hearing aid to understand and possibly solve the challenges of hearing aids.However, if you look for a hearing aid that you can use, you should not use our prototype.Best regards,Marc

author: Audioguru
author_rank: Super Contributor
timestamp: November 25, 2018, 05:06:12 pm
content: I am an old audio-loving guy. I love the sounds of nature, music and voices.But I have normal-for-my-age (73) severe high frequency hearing loss but low frequencies have almost no loss.I thought about making huge hearing aids until I had a free hearing test and demo hearing aids to try out.They are tiny, the frequency response is perfect, they produce no noise and no distortion, they have compression that cannot be noticed (recordings, radio and TV audio compression is obvious and awful), they have 4 microphones with directionality, they have switched automatic noise reduction, and they have switched extra sensitivity and switched muting. They have wireless communication between each one and external products. They play a telephone sounds in both ears.I am glad I bought them (partially paid by my government) instead of making them. They make my hearing young again and their tricks do things normal hearing cannot do.

author: spec
author_rank: Frequent Contributor
timestamp: November 25, 2018, 05:26:56 pm
content: Very informative... and interesting

author: Audioguru
author_rank: Super Contributor
timestamp: November 25, 2018, 05:38:03 pm
content: I watched and tried to translate the video but my hearing aids could not make that woman talk without her severe accent.The woman said it is normal to lose high frequency hearing then everyone tells her to "get used to it". I never got used to being deaf but now when I put my hearing aids on in the morning it takes a few seconds to get used to hearing normally. When I take them off each night then I am suddenly very deaf.My hearing aids do not have the problems of having no mode selections, they produce no feedback and they do not produce all the noises of her hair brushing on them. I never knock on my scull like she does and just now I tried it with and without my hearing aids, the knocking sounds the same. Wind noise is barely noticeable. I never "plug them in to power them" since each cheap tiny button battery lasts for 10 days.The audiologist tried converting the highest octave to a lower octave but it made sounds weird so he boosted the highs to do it instead.My required boost is about double the amount possible with a simple tone controls circuit.

author: chris_leyson
author_rank: Super Contributor
timestamp: November 25, 2018, 08:19:33 pm
content: One DSP chip that sprang to mind was AMI Semiconductors BelaSigna 200 because of its weighted overlap add FFT filter banks and on board dual 16-bit ADC and DAC. AMI had a range of audio processors and hearing aid chips, BelaSigna, Tocatta, Ezairo etc. AMI is now part of OnSemi.

author: WonderWheeler
author_rank: Contributor
timestamp: November 25, 2018, 11:14:20 pm
content: Good comments all!Clarification: yes it is not a "product". We are pretty much all experimenters and hobby-ists on this web site, EEV Blog. I am just trying to promote discussion a little and get the information out there to other people that might be interested. Maybe it will help others.Yes, carrying a bunch of stuff in a fanny pack is kinda lame. Who knows what the battery life is, but there is plenty of room for more battery power if needed. To tell you the truth, I wish I could also add a Google Glass type headset also. Something to add visual cues that someone is talking while I am sitting at my desk for instance. Maybe even a simultaneous speech to text option some day. I'm not too proud of a dorkey nerd to look a little like a cyborg.For people that are interested in the technical parts of the hearing and software process, here is another video I found, mentioned in Peggy's talk:

author: spec
author_rank: Frequent Contributor
timestamp: November 26, 2018, 06:07:25 am
content: Quote from: Audioguru on November 25, 2018, 05:06:12 pmQuite a difference between the hearing loss of men and women- I wonder why that is? Maybe it's because women's ears are not used much- they do not listen that often

author: Carrington
author_rank: Super Contributor
timestamp: November 26, 2018, 02:57:39 pm
content: Maybe, would be great to be able to shift a fecuency (or a range) in real time. For example, almost nobody can hear 20Hz, so now imagine that you move those 20Hz to 40Hz.Also, if I'm not wrong, some people in addition to normal hearing loss (associated with age) cannot hear certain frequencies, but in a discrete way (for example let say they can hear 4000Hz, but not 3500Hz). So in these cases shifting frequencies may be useful, although I'm sure it's not as easy as shifting and that's it...I still hear without problems from ~ 33 Hz to ~ 17 KHz (I never reach up to 19KHz, I think), but I have started to hear a constant whistle around 10KHz (tinnitus) for some time now, so something's starting to go wrong.

author: WonderWheeler
author_rank: Contributor
timestamp: November 26, 2018, 11:06:35 pm
content: Being hard of hearing is not all bad. I used to be super sensitive to things like babies crying, the scream of a Skil-saw, the buzzing of a honey bee around my head. The loss of high frequency sound for me has disabled much of that emotional reaction. Exposure to gun shots, explosions and gunfire from WWII reenactments, industrial noise from working in an almond huller, hammering on 2x4's while one was against my left ear, loud rock and roll music from headphones, riding in an empty metal frieght car on old tracks across the desert at full speed when I was 22, have left its mark.Most of this stuff does not damage the hearing of women. Because they are not exposed to it. But men like to do dangerous stuff, and will put up it.

author: BrianHG
author_rank: Super Contributor
timestamp: November 27, 2018, 12:21:19 am
content: If you want to carry around a microphone & video camera following who you are looking at with an NVidia GPU for the required neural net processing horse power (plus battery pack to power it), with noise canceling headphones which have audio in, you can make a hearing aid which will completelyroastto hell and back compared to anything you can buy today using this AI based speech separation technology:https://youtu.be/rVQVAPiJWKUFull article:https://looking-to-listen.github.io/

author: WonderWheeler
author_rank: Contributor
timestamp: December 03, 2018, 08:42:50 pm
content: Neural net computer is the hard part. Amazing concept though.I was able to translate the ELV SMT preamp instructions article from their journal if anyone needs that, I can create a pdf of the two pages in English. I finally got 4 kits on the way. It turns out they don't ship directly outside the EU except the UK, so I had to use something called mailboxde.com as a third party to ship to me. Maybe ELV didn't want to put up with Trump's bs tarrifs and stuff. Work is progressing.

author: WonderWheeler
author_rank: Contributor
timestamp: January 27, 2019, 02:44:25 am
content: Just finished the two preamplifers that go with the system This old dog was new to surface mounted kit making. Ended up getting some solder flux from Home Depot and used the toaster oven. Its taking a lot of time but its not all wasted, am learning stuff.

author: Audioguru
author_rank: Super Contributor
timestamp: January 27, 2019, 09:54:47 pm
content: A while ago I was blind with cataracts in both eyes. In addition to having free replacement lenses paid for by my government, I paid for eye surgery to correct astigmatism that most old people get.The result is wonderful.The result of me having my government partly pay and me to pay the remained for my modern hearing aids is also wonderful.I am not rich but I do OK.I think in the future, hearing aids will have a "Google Assistant" built-in with languages translations.

author: WonderWheeler
author_rank: Contributor
timestamp: January 28, 2019, 02:08:44 am
content: I am so jealous that your government will do that for you.Yes, I like the idea of integrating a computer into an assisted hearing system. I am often sitting at a desk or using a fanny pack anyway, so there is no need for me to try to cram all the electronics into my ear, miniturizing even the battery. Its a bit crazy using a raspberry pi, but there is some sense to making a compartmentalized system. Yes even speech translation becomes a possiblilty

author: WonderWheeler
author_rank: Contributor
timestamp: March 04, 2019, 11:43:00 pm
content: Latest update:So far its a complete failure. Finished the project, but it doesn't work. Had added a video screen to the Pi, but no image. No indication that it works at all. Nothing. Maybe the SD card was corrupted when the unit was powered down, don't know. Can't tell if it ever worked. The sound card hat for the Pi has pins on the bottom of the RCA jacks that could have pierced the battery UPS battery hat ,don't know. No joy in Mudville. Anyone have ideas? Seems to be a blind alley.

author: mrs
author_rank: Newbie
timestamp: March 12, 2019, 09:19:55 pm
content: The next step is to find out how to boot a Raspberry Pi and check that it booted correctly, e.g., [1,2].https://raspberrypihq.com/booting-the-raspberry-pi-for-the-first-time/https://projects.raspberrypi.org/en/projects/raspberry-pi-setting-up

author: WonderWheeler
author_rank: Contributor
timestamp: August 02, 2019, 11:24:31 pm
content: Yes, the first time I used the regular Windows 10 formatter, did not know I had to install a special SD Card Formatter program. That was part of the problem.Had to install SD Card Formatter:https://www.sdcard.org/downloads/formatter/index.html

author: techman-001
author_rank: Frequent Contributor
timestamp: August 02, 2019, 11:59:14 pm
content: Quote from: Audioguru on November 25, 2018, 05:06:12 pmThey can also be enormously expensive around $10,000 AUD, so for some, making a kit may be the only affordable option.