The Raspberry Pi Hearing Aid

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Group Design Project
A low cost, open source hearing aid for use in research
Group Members
Tom Bate, Tommy Hardman, Jonathan Melling, Jonathan Sandman, Charles Saunders, Tai Jei See

Supervisors
Dr Stefan Bleeck, Professor David Simpson

Supporters
Colsan Electronics

Commercially available hearing aids are expensive ‘black boxes’ of signal processing, which only allow for a handful of parameters to be changed. This limits the level of customisation for each hearing aid user. The project aims to enable researchers’ to access all signal processing algorithms, by producing a low cost, open source hearing aid. The Raspberry Pi 2 Model B was the chosen platform for the hearing aid system. The signal processing algorithms were primarily implemented in Python with some integration of C.

The final system is a single channel, 5 octave-band hearing aid that has been developed in a modular fashion to allow for easy modification of the signal processing chain. The following algorithms were implemented: gain, filtering, compression, noise reduction and feedback control.

3D printable models were developed, based on behind-the-ear and in-the-ear styles. The overall objective performance of the system was satisfactory, as all of the signal processing algorithms were functional. However, the subjective performance yielded unsatisfactory results, due to the overall system producing a high roundtrip latency.
Future work may lead to better latency performance, especially as advancements in technology provide more powerful platform options. Furthermore, successful implementation of multi-processing will enable the utilisation of all CPU cores, and therefore improve the overall efficiency of the software. Other future improvements may be a 3D printed case for the Raspberry Pi Hearing Aid, the installation of touchscreen interface, and wireless audio using Bluetooth.

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  1. Pingback: A Fork in the Road: Where is Audiology Heading? | hearington

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