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]
Vlorbschnat @ instructables.com writes:
What follows are instructions for constructing a battery powered portable VU meter, as well as detailed instructions for the construction of the PCB needed to complete this project. It was designed to illuminate from 0-10 LEDs depending on ambient sound levels. I designed it to be attached to a wristband, clothing, or a necklace if the design is scaled down somewhat. Its purpose is to be worn in a nightclub or similar locale where music is playing, as an animated alternative to a glow stick. It can be used, however, for a variety of alternative purposes.
Battery Powered Portable VU Meter - [Link]
This project was inspired by the “Big Air” open baffle system by Jim Strasser (please contact me for additional information regarding that system). That Big Air open baffle is a simple good sounding system based on a different woofer, smaller baffle and does not incorporate a few other things that I have added. My target cost was to build a pair of open baffle speakers for under $150US. In exploring the possibilities of open baffle speaker systems I reviewed numerous sources to gain an understanding of how they function.
COBIES – Cheap Open Baffle Speakers - [Link]
Although this kind of voice effect can be obtained by means of some audio computer programs, depending on the equipment you are using this microphone input and loudspeaker output could be more versatile. This design uses a variable gain microphone preamplifier built around IC1A, a variable steep Wien-bridge pass-band filter centered at about 1KHz provided by IC1B and an audio amplifier chip (IC2) driving the loudspeaker.
Telephone Call Voice Changer – [Link]