m-r-s / hearingaid-prototype

Instructions for building an almost consumer hardware based prototype of a hearing aid

A mobile hearing aid prototype based on openMHA

This repository holds the information to build a mobile prototype of a hearing aid based on the open Master Hearing Aid (openMHA), a free software platform for real-time audio signal processing. We developed this prototype for a lab course at the Carl-von-Ossietzky Universität Oldenburg and found that the building instructions could be of public interest.

Corresponding author: Marc René Schädler

Mailing list: [email protected] (let me know if you want to be added)

Aims

The prototype was deliberately designed using affordable consumer hardware and open source software. The aim is to lower the entry barrier for hearing aid development and facilitate any interested person to get actively involved in testing and improving hearing devices; empowering power-users.

Warning and disclaimer

First, a few words of warning:

Hearing aids are medical products! You use these instructions and the software at you own risk. The described device can produce very high sound levels. Exposure to high sound levels can permanently damage your hearing! You are responsible for the configuration of the device and the protection of your hearing.

Please read about the consequences of noise induced hearing loss before proceeding to the fun part: https://www.nidcd.nih.gov/health/noise-induced-hearing-loss

Main ingredients

Hardware:

• Binaural Microphones/Earphones
• Microphone pre-amplifier
• Raspberry Pi 3 model B
• Low-latency sound card
• USB power bank
• Bluetooth remote control

Software:

• openMHA
• Raspbian
• JACK
• hostapd
• OpenSSH
• GNU/Octave
• festival-lite

Main characteristics

• Free software: Control is yours, you can change every single bit of it!
• Efficient real-time implementations of research-approved hearing algorithms (c.f. openMHA at Github)
• Competitively low delays: Less than 5ms
• Looks like wearing in-ear headphones
• Whole setup fits in a belt bag
• Sum of all components is about 250 €

Some cool features

• Pre-configured SD-card image (~500 Mb) available for download!
• Pre-calibrated for most "transparent" acoustic impression
• Autostart on boot
• Several hours of autonomy
• Remote control via Bluetooth game pad
• Connect via WiFi to the hearing aid prototype
• Simulate impaired hearing with threshold simulating noise
• Fit it to your hearing thresholds
• Fit it to arbitrary hearing profiles using openMHA's graphical fitting interface
• Extend openMHA with own algorithms
• Combine it with any jack-based software (play, process, or record)

Instructions

This page is only a teaser :) The files in this repository only contain the employed openMHA configuration file, a start script, and some example configuration files. The actual instructions are deployed in the corresponding wiki. Feel free to test them and contribute. Be sure to read the openMHA documentation (pdf files) if you want to dig deeper into signal processing for hearing aids.

hearingaid-prototype's Issues

Bluetooth remote mic

Hello,

With newer hearing aids such as Oticon Opn supporting bluetooth connectivity, can this be used to develop a remote mic or interconnected table mic's for meetings similar to Phonak's Roger Mics or Oticon ConnectClip? This mic would stream audio to the bluetooth hearing aids.

This would greatly help with understanding speech in noise, in meetings, and understanding speech from distance lecturers.

Thanks!

execution error in graphics callback function

Hello

When starting "Calitration dialogue" or "in-situ signals"and when starting "Graphical plugin profiler" in the Control Panel
I get the error message mentioned in the title.

Copy from the command window:
`>> javaaddpath mhactl_java.jar

mhacontrol

warning: set: allowing Unit to match axes property units
warning: set: allowing Unit to match axes property units
warning: strmatch is obsolete; use strncmp or strcmp instead
warning: findstr is obsolete; use strfind instead
execution error in graphics callback function
execution error in graphics callback function

execution error in graphics callback function
execution error in graphics callback function`

What can I do?

Thanks

DL2BQA Frank

-Octave on Win10 PC;
-Linux openMHA 4.19.66-v7+ #1253 SMP Thu Aug 15 11:49:46 BST 2019 armv7l;
-Octave 5.2.0 was configured for "x86_64-w64-mingw32".

how to run openMHA plugins

Hello,

im really new to openMHA, but currently working for preperation of my bachelor-thesis on a jack-based audio processing client. which is intended to developed a simulator of hearing aid device. and then my prof recommended me to learn this software, and hoping that i can create my own plugins (dunno what it means, but maybe apply my own algorithm in openMHA client).

i can already run my own algorithm in this hearing aid prototype, but how do i create plugins and runs it ?

thanks for the answer in advance

Access Denied on Putty - headless setup

I keep getting access denied on the putty, even just by following the default username:pi password raspberry setup. I even tried the german keyboard version. I've set the putty to ssh(port 22). If it helps, I only have the pi connected to our router's lan and accessed it via wifi. I have also extracted the image through 7zip, and got a file about with a size of 3GB. I flashed the image using etcher.

Running OpenMHA without the bluetooth controller

Is it possible to install OpenMHA on pi without setting up the bluetooth controller? It appears to be method for directly adjusting some parameters, but for the configuration, we plan to make any sort of adjustments through wifi connection only. I would like to know if it will run without the bluetooth script. Thank you :)

Earphones are back

The Roland CS-10EM Binaural Microphones/Earphones is available again in Europe. On the Wiki-Side Information are given that this binaural Earphones are not reachable.

compile error from cloned openMHA

Hi again! I'm trying to compile openMHA and install it. but I get a missing header file error for not being able to find sndfile.h

I simply used the git clone command, cd openMHA, then wrote the ./configure && sudo make
I also tried ./configure && make
am I supposed to get the file(s) elsewhere?
it is most likely that I'm doing something wrong. If so, please tell me.

Preamplifier remplacement

The suggested preamplifier can be ordered only in few countries, then needs to be modified which includes SMD soldering. The authors say that no ready off-the-shelf preamplifier could be found. I would like to ask, what is so specific about the preamplifier? If it cannot be replaced by, say, this (one of many options):

https://www.kemo-electronic.de/en/Light-Sound/Amplifier-Splitter/Modules/M237-Stereo-Preamplifier.php?faq
9 - 24 V/DC stabilized (or battery) | Current consumption: approx. 3.4 mA ± 20% at 12 V (without load) | Frequency range: approx. 8 Hz - 60 kHz, 3 dB at U out 1.5V RMS | Input impedance: 100k Ω | Output load: > 2k Ω | Amplification: approx. 30 dB ± 20% | Distortion: ≤ 0.02% ± 20%

then what is the exact reason? Noise level? In particular, is the signal inversion of the original amplifier important? If yes, it seems like something easily modifiable in software.

(mhafw_lib) IO error: (mhajack) Unable to connect to JACK server 'default' as client 'MHA'.

I had this issue when I tried to run gain_live_getting_started.cfg. I deleted jack2 and redownladed it.
Another separate issue that prompted me to delete jack2 in the first place is how do you set the buffer size in Jack? Jack had it set at 512 and openMHA wanted 64.

Recommend mic and pre-amp?

I'm newbie in hearing aid development and aundio I/F.

I bought audio injector, and set up with Raspberry Pi .

I'd like to know the recommended microphone and amplifier (mobile ready).

Also, audio Injector has ECM type mic, is there any problem with this mic?

Detailed Quick start

Moin Marc,
habe gerade versucht im Wiki die Seite "Detailed Quick start" zu erstellen. Bekomme allerdings den Fehler 404 bei speichern der Seite und Github schlägt mir vor, dich zu kontaktieren. Vielleicht weißt du ja weiter?

Lg
Max

jackd will not start

Hi,

I've been trying to get this project up and running for two days.
Unfortunately I can't get the jackd started.
There is always the error message: JackAudioDriver::ProcessAsync: read error, stopping...

I tried both, the complete image and an installation via stretch lite.
In both cases the same result.
The sound card itself is fine and also the microphone amplifiers work.

Anyone else have an idea?

Thank you
Henri

H

how to install this plugin?

Hi,
We have tested the openmha on our windows PC. It works fine. Now we want to install your plugin. How to do it?

Latest image will not flash

i get this error when i try to flash the current complete image on my raspberry pi 4.