Eric Rosenthal and Michelle Temple have developed a low cost open source DIY hearing assistive device through hole component kit called Wear. Wear is a device that was made to provide a low-cost hearing aid alternative for individuals who suffer from hearing loss and is designed to be used when a hearing impaired individual is interested in having a quality conversation in very noisy environments like family gatherings, restaurants or meetings.
This wearable assistive device has been engineered and designed to improve the quality of conversation, while aiding in reducing extraneous noise. Similar to listening to your iPod, users connect their personal headphones to the device that is worn around the neck. The microphone creates a directional sound lobe 3-6 feet in front of the user. The device amplifies sound directly in the circular zone in front of the user, while reducing noise outside of the zone. The Wear can also be used as a high quality commentatorʼs microphone, for interviews or for general recording.
Latency (delay) imposed by digital signal processing is detrimental to the hearing impaired due to lip sync (lip reading) difficulties. For that reason we used an analog circuit design with no measurable latency. We incorporate a technology using a beam-forming array of 10 microphones that create a circular 6 foot zone. Acoustic waves generated in that zone (coherent) reach the microphones at the same time so they are amplified. Sounds from further away (non coherent) reach the microphones at different times are not amplified. This creates a near field to far field signal level difference of 10 to 11 db. That 10 db level difference improves the intelligibility of near field conversation. Our research over the past two years has allowed us to reduce the size of beam forming arrays to unprecedented small form factors in a lightweight package using low power. All of this is done without digital signal processing while maintaining hi fidelity sound quality so that the directional microphone can also be used for general recording applications as well as an assistive hearing appliance.
The open source kit uses through hole components and comes complete with double sided circuit board, all components, a battery, and assembly instructions.
Wear – A wearable personal assistive hearing device - [Link]
The basis for this tube preamplifier started out as a post in the Super simple single stage tube preamp thread on the website Forum. One of the members (see Mark’s 4S Universal Valve Preamps) had suggested building a Super Simple Single Stage Preamp (“4S” Preamp for short) and there was much discussion concerning various tubes, gain, noise, etc. and several designs were presented using various dual triode tubes. Then the proverbial gauntlet was thrown down with the phrase “switch from 12AU7 to 12AX7″. My answer was to design a universal line stage preamplifier that would work well with an entire range of tubes. Thus was the 4S Universal tube preamplifier born.
4S Universal Preamplifier for 12A*7 Tubes - [Link]
Make your own computer speaker system. This simple and inexpensive project will let you set up a small audio amplifier circuit and let more sound out your computer.
A simple audio amplifier circuit based on the LA4440 IC. This circuit will take your computer’s headphone level output and amplify it to drive a pair of external speakers. If you are listening to music or movies on laptops and computers, this is a useful little project for you. Laptop speakers are never loud enough to give satisfying listening. They give users the ability to hear something, but for anything like music or movie soundtracks they are very poor performers. The output from a laptops built in speakers is just too low, and this circuit addresses that low power with some additional amplification.
This circuit uses an LA4440 and some supporting components to give you much more power, while retaining a small package that you can use. The LA4440 is a dual channel audio power amplifier, with low distortion, and a good frequency range. Using 2 channels, the LA4440 will output 6 watts per channel, that can drive much larger speakers than a laptop can hold. When you set up a small enclosure(s), a 12V power supply, and an audio jack connection to the laptop you’ll have a nice enhancement to your laptop audio enjoyment.
Laptop Audio Amplifier - [Link]
Medical grade hearing aids are very expensive, if a person needs help hearing but not necessarily the full cost and capability of a prescribed hearing aid, this might be an option.
This is a less expensive, and DIY option for a hearing aid. It is not a substitute for a real hearing aid that an audiologist would prescribe. Amplification of all sounds and frequencies, or constant use in loud environments can cause additional hearing loss. This circuit could be helpful for some types of hearing loss and occasional use, as well as fill in during the average amount of time people wait to get a hearing aid (7 years).
The condenser microphone picks up acoustic signals, that then pass through the preamplifier stage composed of Q1, a BC547 transistor and a few resistors and a capacitor. The output from the BC547 preamplifier is then fed into the input for the amplifier circuit through the variable resistor R1 and C2. IC1 is the amplifier, a TDA2822M which is designed for low-power portable applications, and in this case, the output is bridged to drive the single earphone. A small LED is included to indicate power status and hopefully remind you to turn it off when you take it out.
A Low Cost Hearing Aid - [Link]
Raffael @ code-bude.net build a webradio by himself. It’s made from an Arduino, an hacked TP-Link WR703N router and some interface parts.
Today I want to present you one of my larger craft projects. This time it is not just about software, but also about the associated hardware. What is it? A web radio!
I like to listen to internet radio stations, but I didn’t want to run my pc only for listening to webradios. Connecting my phone to my stereo either wasn’t a solution, since I’d rather wear this with me, because I don’t want to run for each SMS / Whatsapp message to the music system. And because I always like to tinker, it was obvious to build a web radio as a standalone device myself.
RadioduinoWRT – a do it yourself webradio - [Link]
Gio Militano writes:
Until recenty my desktop computer has always shared a room with a Hi-Fi setup so there has never been a need for using decent speakers with the computer. When the desktop computer was moved into it’s own room (with no HiFi) I quickly realized that good speakers were now required for decent quality music playback. I had been using some low cost Radio Shack speakers with an inexpensive Tripath based amplifier and I was really itching for an upgrade.
Fostex FE103En Bass Reflex Bookshelf Speakers - [Link]
Op-amp Based Preamp for Moving Magnet (MM) and Low Output Moving Coil (LOMC) Phono Cartridges
This project is a departure from that of my normal sort. It is based around an operational amplifier (op-amp)… Yup I’ve transgressed to the dark side. Actually I have nothing against integrated circuits (IC) or solid state devices and in fact use a number of solid state components in my designs. This project is for a relatively simple high performance phono preamplifier that can handle both moving magnet (MM) and low output moving coil (LOMC) cartridges. The basis for the project was a temporary need to have a LOMC preamp in addition to the valve (vacuum tube) ones I have to study low noise performance. Without trying to start any arguments, I have found that it is a lot easier to make a low noise high gain solid state circuit than it is to do the same for valve circuit of similar capabilities. The circuit I came up with is pretty much like many common op-amp based phono preamplifier circuits.
DIY OPA2134 RIAA Phono Preamplifier (MM / MC) - [Link]
Kyocera has developed an ultra-thin, lightweight audio device, dubbed the Smart Sonic Sound, based on the company’s fine ceramic technology.
The 1mm-thin speaker uses a piezoelectric actuator combined with a special film to create a piezo film speaker, enabling the manufacture of very thin TVs, PCs and tablets with improved audio quality. The device’s low directivity characteristics broaden the sound projection range, providing 180-degree sound quality and bringing delicate and minute sounds to life, says the manufacturer.
This piezo actuator audio technology is already in use, LG Electronics integrated it into its 55” curved-screen OLED TV. Smart Sonic Sound comes in three different sizes, 70×110×1.5mm, 35×65×1.0mm and 19.6×27.5×0.7mm, with respective frequency ranges of 200Hz to 20kHz, 500Hz to 20kHz and 800Hz to 20kHz. They weigh 23g, 7g and 1g respectively.
1mm-thin, lightweight piezo film speaker targets thin TVs, tablets - [Link]
Bruno Putzeys writes:
I hate articles titled “Ten … myths debunked.” I would have to start by listing a round number of clumsily worded claims by the non-feedback camp who probably never said any such thing, and juxtapose some simplified school-book explanations to put them right. And after shooting, flaying and roasting alive my straw men and generally hammering home that feedback doesn’t work like that, I should then fail to explain why not. This would leave an excellent status quo where everyone has had their say and truths remain somewhere in the middle.
Negative feedback in audio amplifiers: Why there is no such thing as too much - [Link]
The cMoy is a headphone amplifier kit based around a single dual-channel opamp, suitable for use with portable audio equipment, smartphones, computers etc. It is based on a design well-known in the DIY Audio community. Akafugu writes:
We’ve partnered up with Praktisk Audio, a newly launched audio brand and made it into an open source hardware kit that is easy to assemble for anyone looking for a starting point into the world of DIY audio.We use high-quality parts sourced in Japan, including Rubycon capacitors and a NJM4556AD opamp. The potentiometer is a 10kΩ ALPS potentiometer with built-in on/off switch.The cMoy comes as a kit, and includes the PCB board and all the components you need.No amplifier would be complete without an enclosure, so we are offering a choice of two beautiful aluminum enclosures. Both are Made in Japan by the company Takachi.The standard enclosure is in aluminum with custom-made black acrylic front panels. The deluxe enclosure comes with beautiful custom-cut aluminum front and back panels with high-quality silk screen.
Cmoy Headphone Amplifier Kit - [Link]