Improving Headphones By Voiding Warranties

February 5, 2012 by Brian Benchoff 34 Comments

[Dan] had been wanting a pair of Bluetooth headphones for quite a while. Most of the reviews for wireless headphones in the $50-$80 range complained of tinny sound and dropped bass. Nevertheless, he stumbled upon a $20 pair of headphones with similar reviews and realized that he could switch out the driver and make a decent pair of cans.

The donor drivers came from a pair of Sennheiser HD 540 headphones. These are very respectable headphone speakers that cost about what you would expect for pro audio gear. To to get Bluetooth working with the Sennheisers, [Dan] removed the PCB and battery enclosure and attached them to the headband with velcro.

For his build, he had to cut the cable on the Sennheisers and solder them to the Bluetooth board. There was never any danger of ruining a good pair of headphones, though. If he screwed up he was only out a headphone cable. Now [Dan] has a nice pair of Bluetooth headphones that can reproduce bass. Not a bad deal for a $20 pair of headphones.

Rotary Phone-light-amp Could Be Filed Under Bizarre

January 25, 2012 by Mike Szczys 18 Comments

[Samimy’s] latest project is a little strange, but one man’s weird is another man’s wonderful so we’re not about to start criticizing his work. Nope, we’re here to praise the fact that his rotary phone turned reading light and audio amp is very well constructed.

He started by removing the phone housing. Those old enough to have used one of these devices will remember their bulk, and there’s a lot of unused space in both the handset and body housing. [Samimy] started by removing the speaker and microphone from the handset, and drilling a ring of holes to receive white LEDs. The circuit was wired so that lifting the handset turns on the lights.

But he didn’t stop there. A set of speakers and the audio amplifier circuitry from an old tape deck are also hiding inside the base of the phone. If you look closely in the image above you can see that he’s connected his cellphone and is listening to some tunes through the antique hardware. Take a gander at the video after the break to see construction and use of the project.

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NES Controller Cannibalized For MP3 Player Enclosure

January 19, 2012 by Mike Szczys 20 Comments

We know some folks are very upset by the scrapping on vintage hardware, so let’s all observe a moment of silence for this NES controller.

Now that that’s behind us we can live vicariously through [Burger King Diamond’s] project. He polished up the NES controller and repurposed it as an enclosure for a portable MP3 player.

His first step was to remove some of the yellowing of the plastic using Retr0brite. He admits it wasn’t bad to start with but now it’s sparkling like new. Next, he started planning how everything would fit in the case. Luckily the MP3 player operates with one AAA battery which leaves plenty of room.

Just above the A and B buttons you can make out an opening that he cut in the case for the MP3 player’s LCD screen. The bezel from the original case works well for cleaning the rough cut opening. The buttons on the controller have been patched into the controls on the MP3 board, and the opening for the controller’s cable now holds the headphone jack. There’s also a USB port mounted next to it for easy file transfers.

The one thing we would like to see is a rechargeable battery so you don’t need to open the case to top off the power. But all in all this is a fantastic build!

Adding Sound To Children’s Museum Exhibits

January 17, 2012 by Mike Szczys 17 Comments

Believe it or not, the local Children’s Museum staff was happy that [Bill Porter] left this mess of wires and equipment in one of their offices. It makes up an ambient sound system for a couple of their exhibits. A movie without sound just doesn’t fully entertain, and the same can be said for these exhibits. The ambient sound that goes with a boat room, and a hospital room in the Museum really helps to snag your attention. And [Bill’s] material cost came in at just over $200 for both rooms.

He started off by purchasing a speaker, amp, and MP3 breakout board (SparkFun). The speaker mounts in one of the ceiling tiles, with the wire running to a different room where the audio equipment is housed. There were a couple of problems with this; the museum staff forgot to turn on the system, and for all of its expense this only provided one room with audio. Bill figured that since only one speaker was being used he could make an audio file with a different clip on the left and right channel, then feed them to different rooms. He also added that programmable timer so the sounds will turn themselves on and off.

This isn’t the first time we’ve seen hacks end up as museum pieces. Check out this other project that rigs up some interactive telephones.

$3 Adds Sweet Tunes To Your Project

January 16, 2012 by Mike Szczys 19 Comments

It’s a fun time to design your own MP3 player, lovingly adding in features to a meticulously crafted user interface. But sometimes you just want a quick and cheap way to add music to a project. [Jeff Ledger] will show you how to do just that using some knock-off hardware from overseas. Instead of a proper breakout board — which can cost a bundle — he used a generic MP3 player acquired for $3 from an eBay seller.

Cracking open the case you’ll see that you actually get a lot for your triad of Washingtons. We know, it may be of questionable quality (see this feature about cheap PSU problems) but we’re not building mission critical hardware now are we? Inside is a rechargeable Lithium battery for use with another project, and a chip-on-board device with attached SD card slot, audio jack, and USB port. The battery inputs are used to solder the MP3 pcb to the power rails on your project. To control the playback, just make connections to the button pads as [Jeff] describes in his post. It sounds like this will work with any MP3 player which runs at either 3.3V or 5V.

Microcontroller Based Audio Volume Level Compressor

January 11, 2012 by Mike Szczys 18 Comments

In an effort listen to his music on shuffle without the need to touch the volume knob [Mike] build his own automatic volume leveling hardware. He knows what you’re thinking right now: there’s software to do that for you. But building the feature in hardware is a great stepping off point for a project.

He started the prototype using LabVIEW along with a Mobile Studio development board and a Bus Pirate. This project will be a mix of digital and analog components and it’s a bit easier starting off the exploration with these tools rather than jumping right into the AVR code.

The circuit will sample the incoming audio, modify it accordingly, and output the result. The output side is where the Bus Pirate really shines. He’s using some MCP42010 digital potentiometer chips to make the necessary changes to the levels. They communicate via SPI and it’s nice to have the Bus Pirate’s terminal to issue commands without the need to reflash a microcontroller.

[Mike] made a video showing an audio waveform with and without the hardware leveling. Sound quality is still great, and each clip is played at a reasonably comfortable listening level. We’ve embedded that demonstration after the break.

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Snap Together Boombox Great For Taking Your Music On The Go

December 23, 2011 by Mike Nathan 14 Comments

fab-boombox

[Matt Keeter] wanted to take his music on the go, and wrote in to share a great looking boombox he built for under $100. His goal was to put something together that could be made in pretty much any hackerspace/fab lab, so his boombox was made using simple materials.

He first modeled the boombox using cardboard, later fabbing it from wood on a laser cutter. The design allows the stereo to be snapped together, though [Matt] says that some joints were glued as an extra precaution. Inside the boombox resides an custom PCB he built which incorporates an ATmega328, an MP3 decoder, and an SD card to store his music.

One feature we really like is the control scheme [Matt] built into the boombox. Each of the capacitive touch buttons are positioned on top of a copper pad, which are wired into the control board. He says that while good in theory, he had a difficult time getting the buttons to work properly, though they seem to do the job well enough.

If you’re looking for a portable music solution and have access to a laser cutter, be sure to check out [Matt’s] page for schematics and firmware.