Year: 2012

Reverse Engineering Old PDA Software

March 13, 2012 by 13 Comments

[Troy Wright] acquired a lot of twenty broken Dell Axim PDAs. This type hardware was quite popular a decade ago, but looks archaic when compared to a modern cell phone. That’s why he was able to get them for a song. After a bit of work he managed to resurrect eight of the units, but was dismayed to find there’s no published method for controlling the back light from software. For some reason this is a deal-breaker for his project. But he knew it was possible because there are some apps for the device which are able to set the back light level. So he found out how to do it by reverse engineering the software.

The trick is to get a hold of the code. Since it’s not open source [Troy] used IDA, a graphical disassember and debug suite. He had some idea of what he was hunting for as the Windows CE developer documentation does mention a way to directly control the graphical hardware independently from the display driver. A few hours of pawing through assembly language, setting break points, and testing eventually led him to the solution.

Playing MP3s From An FPGA

March 13, 2012 by 7 Comments

Building an audio player is a fun project. It used to be quite a task to do so, but these days the MP3 decoder chips are full-featured which means that if you know how to talk to other chips with a microcontroller you’ve got all the skills needed to pull off the project. But that must have been too easy for [Ultra-Embedded], he decided just to build an MP3 player out of an FPGA.

It’s not quite as difficult as it first sounds. He didn’t have to figure out how to decode the audio compressions. Instead he rolled the Helix MP3 decoder library into the project. It had already been optimized to run on an ARM processor, and since he’s using a RISC soft processor the translation wasn’t tough at all. He’s using a 24-bit stereo DAC chip to bridge the gap between the audio jack and the FPGA output. Clocking that chip with the FPGA isn’t ideal and causes 44.1 kHz audio to run 3% too slow. He says it’s not noticeable, which we believe. But if you try to play along with a song the pitch shift might end up driving you crazy.

If you’d prefer to just stick to the microcontroller based players this one’s small and inexpensive.

Controlling A DSLR With A Nintendo DS

March 13, 2012 by 4 Comments

At Hack a Day, we’ve seen dozens of intervalometer builds that open and close a camera shutter remotely. [Luke Skaff] decided to take these builds to the next level by automating a camera’s focus and shutter with a Nintendo DS.

[Luke]’s build is based on the Open Camera Controller project that puts the power of an intervalometer, sound trigger, sequencer, and HDR bracket shooting into the hands of professional photogaphers. The Open Camera Controller is built to run on a Nintendo DS with an AVR-based card attached to the Game Boy Advance cartridge port.

The Open Camera Controller attaches to a camera’s shutter port, but [Luke] stepped things up a little bit by using a USB host controller and implementing the picture transfer protocol. Now, instead of [Luke]’s controller telling his camera when to open and close the shutter, the focus of the camera can be adjusted as well. [Luke]’s build uses an Xilinx CoolRunner-II CPLD and a USB host controller to convert the DS cartridge port to a USB port every DSLR can connect to.

[Luke] still has a mess of wires on his hand, but even we can see the power that inexpensive automation would bring to the world of digital photography.

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Brewtarget: Open Source Homebrewing

March 13, 2012 by 14 Comments

[youtube=http://www.youtube.com/watch?feature=player_embedded&v=BEdkZIUkvA4]

Several of us here at Hackaday Brew our own beer. Needless to say, we got a little excited when we saw members of the open source community building a brew tracking system. Brewtarget is an open source tracking system that you could download right now and begin tracking and building your recipes. It looks like there is a fairly active development group working on it and even a feature request form that seems to be filling up. Maybe we overlooked it, but there doesn’t seem to be an existing feature list. We look forward to seeing where this project goes.

Brewtarget implements BeerXML, which means it should also be compatible with Beershmith, a commercial application.

[via adafruit]

Avoid Shaky Camera Movements With Gyroscopic Stabilization

March 13, 2012 by 40 Comments

Right after “no editing whatsoever”, the “shaky camera” is the bane of YouTube viewers the world over. [David] came up with a nice solution to the problem of shaky cameras that uses gyroscopes to even out the bumps of making a great movie.

Most cameras attached to moving frames – from the zip-line cameras at NFL games to police helicopters and aerial reconnaissance drones – have some sort of gyroscopic stabilization. Even though gyroscopic stabilization has been around for more than 60 years, the designs haven’t changed that much. [David] dug up a few patents dating from the 50s and set to work replicating the design.

[David] bought a pair of [Glenn Turner]’s fabulously heavy and expensive-looking powered gyroscopes and began bolting them onto a piece of sheet metal. Per the 1950 patent, the gyroscopes were mounted 90 degrees apart and bolted onto the camera.

From the video demo (after the break), there’s a marked difference between filming a stroll though a parking lot with the gyros on and gyros off. While the pair of motor driven gyroscopes look a little ungainly and are a bit too loud for our tastes, the solution is much less expensive than the $1600 professional gyro [David] based his build on.

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Control An Arduino From Android Over Bluetooth

March 13, 2012 by 10 Comments

Whether you’d like to do some real-time logging of data, or just want to control a project with your Android phone, [Thomas]’s Arduino-Android Bluetooth connection instructable is sure to be useful

[Thomas]’ build uses the very inexpensive JY-MCU Bluetooth module that’s available on eBay or dealextreme. This Bluetooth module ties directly into the Tx and Rx lines of the Arduino so a wireless serial connection between an Android device can be established. On the Android side of the build, Python for Android and the Scripting Layer for Android allow for reading wireless sensor data over Bluetooth.

While connecting an Android device to an Arduino is also possible with an IOIO  or an Android Open Accessory dev kit, we haven’t seen much (barring this) about controlling or reading simple electronics with Android over Bluetooth. Sometimes you just don’t need an awesome dev board to bodge up a simple project, so we hope [Thomas]’s very nice instructable will help get a few more builds off the ground.

The Spud Gun To End All Spud Guns

March 13, 2012 by 74 Comments

In Norse mythology, Mjöllnir is the hammer of Thor, forged in a contest to create the most wondrous and munificent tool for the gods of Asgard. While we’re not aware if [MrCrowley] recently made a bet with Loki, his version of Mjöllnir, a gigantic spud gun powered by MAPP gas, is wondrous enough for our tastes.

Unlike most of the other spud guns we’ve seen, [MrCrowley] eschewed the use of PVC pipe and fittings in his build because that would explode on the first test fire. Instead, the gun uses galvanized and stainless steel for the majority of the construction. That’s not to say this spud gun is necessarily safe, though: as he demonstrates in the video after the break, golf balls exit the barrel with a comparable energy to most rifle rounds.

For an interesting take on an ignition system, [MrCrowley] built a remote ignition system out of a wireless doorbell and a 100kV stun gun. While this does allow for remote firing, the entire build seems safe enough – from behind the muzzle, at least – to be carried with a rifle strap.

It should go without saying that this is incredibly dangerous and you shouldn’t build this if you’re not planning on your last words being, “Wanna see something cool? Hold my beer.” That being said, [MrCrowley] knows what he’s doing, and you can check out the video of Mjöllnir in action after the break.

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