Wire Loop And Amplifier Solve Audio Problem For The Hearing Impaired

Imagine being asked to provide sound reinforcement for a meeting that occurs in a large room, where anyone can be the speaker, and in a situation where microphones would hinder the flow of the meeting. Throw in a couple of attendees who have hearing disabilities, and you’ve got quite a challenge to make sure everyone gets heard.

Such a situation faced [David Schneider] at his Quaker meetinghouse, which he ended up solving with this home-brew audio induction loop system. The worship style of conservative sects of the Religious Society of Friends, as the Quakers are formally known, is “silent worship”, where congregants sit together in silence until someone feels moved to share something. Anyone can speak at any time from anywhere in the room, leading to the audio problem.

Rooms mics and a low power FM transmitter didn’t work because those using radio as aids to hearing the service felt awkward, so [David] decided to take advantage of a feature in the hearing aids worn by some members: telecoils. These are inductive receivers built into some hearing aids to send sound directly to them using magnetic fields generated by a loop in the listening area. [David]’s loop ended up being 240 meters of 20-gauge copper wire in the attic above the meeting room. The impedance ended up close to 8 ohms, perfect for feeding directly from the speaker terminals of an old stereo amplifier. Pumping 160 Watts into the coil allows the hearing-aid wearers below hear the service now.

There’s still work to be done on the input side to improve audio quality, but [David]’s solution is elegant in that it helps those who need it most using technology they already have. And perhaps those who need but don’t yet have hearing aids can roll their own.

Glasses For The Hearing Impaired?

If you don’t have hearing loss, it is easy to forget just how much you depend on your ears. Hearing aids are great if you can afford them, but they aren’t like glasses where they immediately improve your sense in almost every way. In addition to having to get used to a hearing aid you’ll often find increased noise and even feedback. If you’ve been to a theater lately, you may have noticed a closed caption display system somewhere nearby that you can sit within visual range of should you be hard of hearing. That limits your seat choices though, and requires you to split your attention between the stage and the device. The National Theatre of London is using Epson smart glasses to put the captions right in your individual line of vision (see video below).

The Epson glasses are similar to the Google Glass that caused such a stir a few years ago, and it seems like such a great application we are surprised it has taken this long to be created. We were also surprised to hear about the length of the project, amazingly it took four years. The Epson glasses can take HDMI or USB-C inputs, so it seems as though a Raspberry Pi, a battery, and the glasses could have made this a weekend project.

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Hackaday Prize Entry: Shakelet

A person who is deaf can’t hear sound, but that doesn’t mean they can’t feel vibrations. For his Hackaday Prize entry, [Alex Hunt] is developing the Shakelet, a vibrating wristband for that notifies hearing impaired people about telephones, doorbells, and other sound alerts.

To tackle the difficulty of discriminating between the different sounds from different sources, [Alex’s] wants to attach little sound sensors directly to the sound emitting devices. The sensors wirelessly communicate with the wristband. If the wristband receives a trigger signal from one of the sensors, it alerts the wearer by vibrating. It also shows which device triggered the alert by flashing an RGB LED in a certain color. A first breadboard prototype of his idea confirmed the feasibility of the concept.

After solving a few minor problems with the sensitivity of the sensors, [Alex] now has a working prototype. The wristband features a pager motor and is controlled by an ATMEGA168. Two NRF24L01+ 2.4 GHz wireless transceiver modules take care of the communication. The sound sensors run on the smaller ATTiny85 and use a piezo disc as microphone. Check out the video below, where Alex demonstrates his build:

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