Ugly Upgrade Keeps The Tunes Playing Longer

September 13, 2012 by Mike Szczys 25 Comments

[Sam] picked up a Sansa Clip audio player to listen to some tunes while working on projects. He liked the fact that he could run the Rockbox alternative firmware on the device, but thought the 15 hour battery life needed some improving. He swapped out the stock cell with a larger Lithium cell for a long life of 50-60 hours. It’s an upgrade fom 300 mAh to 1100 mAh, but as you can see, the size of the replacement made for some interesting case modification.

The battery swap required more than just taking one battery out and putting in the other. [Sam] is using a cellphone battery as the replacement and he didn’t want to have issues with the internal circuitry. He took the cell out of its plastic enclosure, removing the circuit board in the process. That PCB is the charging circuit, which he replaced with the one from the stock battery. After insulating the cell with a layer of Kapton tape he soldered it to the MP3 player and did his best to adhere all the parts to each other.

Sure, its ugly, but that makes it right at home on the work bench.

A Laser Audio Transmitter

August 31, 2012 by Mike Szczys 38 Comments

Here’s a way of transmitting audio that makes it virtually impossible for someone else to listen in. Instead of sending radio waves bouncing all over creation, this uses the focused light of a laser to transmit audio. In the image above you can see the silver cylinder which houses the laser diode. It is focusing the beam on a light dependent resistor to the right which looks almost like a red LED due to the intensity of the light.

The simplicity of this circuit is fascinating. On the receiving end there is no more than the LDR, a 1.5V power source, and a headphone jack. The transmitter is not much more complicated than that. It includes an audio output transformer which boosts the resistance of the audio signal. This increase in resistance ensures that the laser diode modulates enough to affect the LDR on the receiving end. The transmitter uses a 3.3V supply. Check out the video after the break to hear the high quality of audio coming through the setup.

Once you’re done playing around with the transmitter you might try turning the laser into a remote control for your stereo.

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Convert A Speaker To A Battery-powered Amplifying Party Box

August 13, 2012 by Mike Szczys 19 Comments

[Matt the Gamer] loved his pair of Minimus 7 bookshelf speakers. That is until a tragic hacking accident burned out the driver and left him with a speaker-shaped paper weight. But the defunct audio hardware has been given new life as a single portable powered speaker. Now he can grab it and go, knowing that it contains everything he needs to play back audio from a phone or iPod.

The most surprising part of the build is the battery. [Matt] went with a sealed lead-acid battery. It just barely fits through the hole for the larger speaker, and provides 12V with 1.2 mAh of capacity. He uses an 18V laptop power supply when charging the battery. The PSU is just the source, his own circuit board handles the charging via an LM317 voltage regulator. Also on the board is an amplifier built around a TDA2003A chip. He added a back panel which hosts connections for the charger and the audio input. Two switches allow the speaker to be turned on and off, and select between battery mode and charging mode. As a final touch he added a power indicator LED to the front, and a drawer pull as a carrying handle.

Sound-o-Light: Simple And Interesting DIY Speakers

August 9, 2012 by Caleb Kraft 12 Comments

This is a great project for a slow afternoon, or a beginners introduction to DIY. [William] shows off a really simple speaker project that results in a light show as well as a decent enclosure. He’s using a PVC elbow to mount the speakers. They’re just glued in place. Below that, a section of clear tube allows for the lighting effects and a flange at the bottom supplies stability. For the lights, [William] opted to forego any complicated electronics and simply wired LEDs to the speakers themselves.

Admittedly we’ve seen more complicated systems in the past, but his results are quite nice and could be done pretty fast.

Building An Isolation Booth For Your Home Recording Studio

August 2, 2012 by Mike Szczys 34 Comments

[Brattonwvu] wanted to lay down some tracks with as high an audio quality as possible. To help get rid of the noise pollution of the everyday world he built this isolation booth in his attic.

The project started off with a trip to the home store for some 2×4 stock and OSB to use as sheathing. The framing is as you would expect, but to help deaden the sound he went with a surprising material. He’s filled the cavities between each 2×4 with stuffed animals and old clothes. The same is done in the walls and the inside surfaces are all covered in fabric to prevent echoing. The door has a lip and we can just make out what looks like weather stripping to provide a seal. There is just one opening in the box, where a PVC pipe allows electrical and microphone cables to pass through. [Brattonwvu] reports that you can hear your heartbeat in your ears when standing inside the sealed booth.

Reworking The Electronics For Better Computer Speaker Audio

July 31, 2012 by Mike Szczys 23 Comments

[Michael Chen] liked the sound he was getting out of these Corsair SP2200 computer speakers, with one big exception. They were giving off some unpleasant crackling sounds. He figured this might be as easy as replacing a faulty potentiometer, but soon found out the fix was going to be more complicated than that. All said and done he ended up reworking the design of the speakers’ amplifier board.

The hardest part was identifying the problem. Once he had cracked open the case he found the volume potentiometer was working correctly by testing it with a multimeter. Next he inspected the board for bad solder joints but didn’t really find any. The breakthrough came when he realized that the crackling was also happening when he used headphones. With that discovery he started making a few more observations and realized that the crackling didn’t happen when the volume knob was all the way up or all the way down. There was an impedance issue between that potentiometer and the amplifier circuit. He rerouted the signal flow on the board to use the headphone amp as a filter and it fixed the problem. Fittingly, he’s entered this project into the Instructables Fix & Improve contest.

Developing A Better Way To Control 10,000 LEDs

July 31, 2012 by Mike Szczys 14 Comments

The SoundPuddle project drives thousands of LEDs based on audio input. The team is working on a replacing the controller for this wire-filled setup with something more robust. They took the mess seen above to the Apogaea Festival and were plagued by loose wires and unreliable communications due to noise and interference. The aim of the new system is to reliably control up to 10,000 LEDs.

The red PCB seen at the center of the rats-nest is a Papilio FPGA board. They still want to use it to drive the installation, but a new hardware interface is necessary. The solution is to design what they call a megawing (wings are to Papilio as shields are to Arduino). The LEDs will be in RGB strip form, so one of the requirements is to supply enough connectors to drive 16 channels of SPI devices. The wing will also include the 48V power source and connectors for the condenser microphone that serves as an input for the SoundPuddle. There are also two other options for audio input, one via a Bluetooth module (which can double as a control device) and the other via MIDI.

After the break you can see a lighting demo. Be ready with the volume controls as most of the sounds used in the test are quite annoying.

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