Important: Zoetrope Labs has decided to close down after 5 great years of business. The team are moving on to new adventures. This site is left up for reference only.

Action On Hearing Loss - Wearable

Zoetrope worked with Action on Hearing Loss as part of a Nesta prize to create a fully functional prototype of a low cost hearing loop device which could be used to assist people with mild to moderate hearing loss. Most hearing aid products target more severe hearing loss at present, leaving a gap in the market for technologies to aid milder cases of hearing impairments.

Nesta have a full write up of the project over on their site too.

The idea

Action on hearing loss has been a UK charity for over 100 years and throughout this time has sought to help people with hearing loss through policy, support and technology. Zoetrope was approached to help create a full working prototype from an early idea.

The goal was to create a device which makes use of a smartphone in order to both increase the utility of the device and allow for a much lower unit cost. The design was to utilise regular headphones for sound output.

The initial concept envisioned all audio processing being completed on the phone, but after Zoetrope’s research it became clear that this would cause an unacceptable delay in this real-time application which meant that an alternative approach was sought.

During the planning and specing phase, Zoetrope helped Action on Hearing Loss develop a workable solution taking into account the original brief and the limitations of audio processing on current generation smart phones.

Zoetrope provided input on all aspects of the design, including some concepts of what the product could look like (below) as well as other ideas, such as how the the product could map the quality of hearing loop systems to build an availability database of the assistive technology.

Early concept sketch of the product design

Zoetrope’s Implementation

Zoetrope created a full working prototype of the hardware, software and Android application, ready for user testing and presenting to Nesta. Zoetrope’s design has all the audio processing completed by custom onboard audio software written in house.

The overall block diagram is as follows: Action on Hearing loss proposal-1

The design’s key features include:

  1. Telecoil sensor for use in many public places such as banks, shops, theatres etc. which all have inductive hearing loop systems available.
  2. Using regular headphones plugged into a bluetooth pendant, which means the device can be used for calls and music.
  3. Control via a smartphone, which allows for a simple to use interface.


Zoetrope created and delivered 5 working prototypes of the loop listener system over a mere 6 week lead time. During this time Zoetrope created/delivered:

  1. A prototype of the electronics for testing, which were tested in Action on Hearing Loss’ testing chamber.
  2. A PCB with the bluetooth, audio processing and analogue electronics for a self contained unit.
  3. The custom audio processing software to process all the audio content in real time.
  4. Customisation of off-the-shelf enclosures to house the prototypes.
  5. An Android application (see screenshot below) which allowed for controlling the devices.
  6. Usage instructions
  7. Support with the trials.

The finished electronics, housed in a customised off-the-shelf enclosure: Finished product

A screenshot of the prototype app: Drawing

Overall, this was a whirlwind 6 week project which was completed within incredibly tight deadlines to help Action on Hearing Loss produce an entry for the Nesta inclusive technology competition. Nesta ultimately did not award the project further budget, however there is scope for Action on Hearing Loss to continue the project in the future.

Header image is courtesy of Nesta

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“This has been one of the most rapid deliveries I have known in the whole industry. ”

James O'Halloran, external consultant to Action on Hearing Loss.