sd card

73 Articles

Building A Media Player With An MSP430

April 2, 2012 by 13 Comments

A media player based on an Arduino and SD card has been done to death several times over, but that doesn’t mean we can’t appreciate [Matt]’s MSP430 audio player. It’s a very nice piece of work that supports a FAT16 file system and only takes up 54 bytes of RAM.

To make his dream of a 430 media player a reality, [Matt] based his work on the DIY Life Talking MSP430 project. Unlike this previous attempt to play music with a ‘430 and SD card, [Matt] threw in a full FAT16 file system, allowing him to drag and drop audio files on his computer to the SD card.

Right now [Matt]’s build can play a stereo audio file through its speakers, but the sound quality over a mono file is greatly reduced. The maximum sample rate is 16kHz; a ‘good enough’ sample rate if you’re listening with terrible headphones. In the video after the break, [Matt] plays this awesome Symphony of Science on his homebrew media player. We’re guessing his camera doesn’t do his project justice, but it’s still impressive nonetheless.

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Building The Worst Linux PC Ever

March 28, 2012 by 123 Comments

Linux is generally considered the go-to OS for under powered computers. Wanting to challenge the preconceived notion that Linux requires ‘a computer made in the last 20 years,’ [Dmitry] built the worst Linux PC ever around a simple 8-bit microcontroller.

The ATMega1284p [Dmitry] used doesn’t have a lot to offer as far as RAM and storage goes; just 16 kilobytes of SRAM and a paltry 128 kilobytes of Flash storage. While this may be voluminous in the embedded world, it’s peanuts compared to the gigabytes of RAM and hard drive space on even a low-end netbook. To solve this problem, [Dmitry] threw an antique 30-pin RAM SIMM at the problem. It’s wired up directly to the microcontroller, as is the 1 Gigabyte SD card that serves as the PC’s hard drive.

Linux requires a 32-bit CPU and a memory management unit, something the puny microcontroller doesn’t have. For [Dmitry], the best course of action was emulating an ARM processor on an AVR. We’re not sure if we’re dealing with genius or madness here, but it did prove to be a valuable learning exercise in writing a modular ARM emulator.

How fast is it? [Dmitry] tells us it takes two hours to boot up to a bash prompt, and four more to load up Ubuntu and login. If you want a Megahertz rating, good luck; the effective clock speed is about 6.5 kilohertz. While the worst Linux PC ever won’t win any races, its simple construction puts it within the reach of even the klutziest of hardware builders; the entire device is just a microcontroller, RAM, SD card, a few resistors, and some wire.

If you’d like to build your own worst Linux PC, [Dmitry] has the firmware and disk image available to download. If you want to watch the time-lapse of this thing booting, check out the video after the break.

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Flash An Arduino From An SD Card

February 21, 2012 by 30 Comments

[Kevin] has been working on reverse engineering the protocol used by the Arduino IDE and porting it to the Arduino platform. Now that his BootDrive project is nearing completion, he’s ready to give every Arduino the ability to program another Arduino over an SD card.

BootDrive isn’t terribly different from using an Arduino as an ISP, only now AVRdude runs on the Arduino itself and no computer is required to put new firmware into the target Arduino.  [Kevin] attached a MicroSD breakout board to an Arduino-compatible clone. When the clone starts up, it searches the SD card for a file called ‘program.hex.’ This file is sent over to the target Arduino and the new firmware is installed.

While it may not be extremely practical if you’ve only got a few Arduinos that never leave your workbench, we’re thinking this would be an invaluable tool if you need to update the software on a board already ‘in the field,’ serving as a weather station or homemade game camera. [Kevin] put up a demo of his BootDrive project; you can check that out after the break.

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NES Controller Is A Slick Way To Carry Around Your Portable OS

November 13, 2011 by 14 Comments

nes-controller-linux-drive

[Oliver] had an old NES controller laying around, and without any other use for it, he decided to repurpose it as a portable storage device.

He gutted most of the controller, removing the plastic standoffs, leaving the D-pad and remaining buttons intact. He crammed a 32 GB flash drive inside, along with the guts from an SD card reader. Using a Dremel he cut several openings into the controller, one for the flash drive and SD card reader’s USB ports, as well as for the SD card itself. When the physical modifications were finished, he installed a small Linux distro on the flash drive, which can be run by any PC that supports booting from USB.

While some might argue, we think it’s a neat way to reuse an old gaming peripheral that he might have otherwise thrown out. The portable OS is something that would certainly come in handy, though we can’t wait until the Raspberry Pi is finished – it would be awesome to have a complete computer packed in there too.

Speaker-mounted WAV Player For Street Performances

August 29, 2011 by 21 Comments

This naked speaker is the basis for [MaoMakMaa’s] newest project called the Wavedrone. He plans on using the autonomous and cable-less device during street performances. You can hear the effect of some stretched jazz cords being played on it in the video clip after the break. The sound is kind of an ethereal background noise that observers might not immediately realize is there.

You can see the 9V battery which serves as the power source clinging to the frame of the speaker. A 7805 linear regulator tames that battery and feeds the two IC’s on the circuit board seen to the right. The ATtiny85 is reading music from an SD card and playing it back in mono (obviously) with the help of an LM386 audio amplifier chip. The trimpots that go into the high pass and low pass filters in between the microcontroller and amplifier allow for a bit of sound manipulation, but we’re more impressed with the quality of the sound this is getting when properly trimmed.

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Sleek, Disc-less GameCube Handheld

July 29, 2011 by 35 Comments

sd_card_gamecube_handheld

Console hacker [techknott] has a skill set that is quite possibly second to none. We do love [Ben Heck] and think that his portable consoles are beyond awesome, but you’ve got to check out this portable GameCube [techknott] put together.

While the construction details are pretty sparse, the video below shows off the bulk of the portable ‘Cube’s best features. Far smaller than his Flip-Top GameCube or Dreamcast portables we’ve featured in the past, his new handheld sports a wider screen and is completely disc-less. While the legality of booting backup copies of games from an SD card is something we won’t delve into, we do like the concept.

The console itself is probably only about one and a half times the width of a standard GameCube controller, and while it doesn’t sport an internal battery pack, we wouldn’t turn one down. Besides, who wants to play GameCube outside? With one of these in hand, we are more than happy to keep our pasty selves indoors, thank you very much.

The only complaint we have here is the lack of build details. [techknott’s] handheld consoles are pretty amazing – we just wish that we could see how the magic was made!

Be sure to check out the video below to see the console in action.

[Thanks, Dave]

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Game Boy Communicates Directly With An SD Card

July 2, 2011 by 26 Comments

[kgsws] just finished his Game Boy upgrade that allows him to load games from an SD card. Loading a game off an SD card has been done before, but [kgsws] decided to not to use a cartridge-based device. In the end, he threw out all the stops and finished his project by having the Game Boy access an SD card directly.

[kgsws] his project trying to figure out how to put some GPIO pins on a game cartridge, but figured that this would take too much hardware. After looking at the specs of the link port, he realized that it was the wrong polarity. Not to be deterred, [kgsws] realized that there was something like a general-purpose I/O on the Game Boy – the joypad input.

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