[Rohit Gupta] wrote in to share this touchscreen piano project he built around the TI Launchpad. It provided a way for him to explore using a resistive digitizer found on a lot of mobile devices. These are simply stuck to the top of LCD screens and replacements are inexpensive, but salvaging one from old hardware is an option as well.
The first thing he did was to test the four outputs of the digitizer with his multimeter. Logging the changing resistance will help make sure you’re reading the correct wires and are able to zero in the settings before you start coding. [Rohit] uses the ADC on the MSP430 chip to read from the screen. He went with the algorithm from one of TI’s app notes to convert the readings in to X and Y coordinates.
He separated the screen into seven columns, each generating a different tone. Touching higher or lower on that column will alter the pitch of the note produced. You can hear an example of this in the demo after the jump.
Filed under: musical hacks
This is going to change the way you play with yourself. What if every time you got a little bored you reached for your belt rather than your smart phone? [Cunning_Fellow] may be doing that more often now that he finished this slick-looking video game belt buckle which plays the classic Asteroids game.
It isn’t just an intriguing concept. The build was pulled off at a very high level of quality… this thing should have no problem standing the test of time. First off he had to figure out if it was even possible to run the game at a respectable frame-rate. Cheap 320×240 LCD screens don’t have a frame marker (think of it as a vertical sync signal with can be used as an interrupt for the microcontroller). But he thought it was possible that the frame marker pin just wasn’t connected like on more expensive screens and he was right with at least one model he acquired.
With that out of the way he laid out and etched a beautiful double-sided board to house all of the electronics. But he still needed a case. To get a one-of-a-kind look he masked and etched a sheet of brass. Once cut out and folded ti gives a wonderful look and protects the electronics inside quite well.
Filed under: wearable hacks
Gather ’round children, we’re about to hear a story about the good old days. Except that this is really more of a horror story of what it used to be like as a code monkey. [John Graham-Cumming] shares his experience programming a 6502-based KIM-1 machine back in 1985. Simple, right? The caveat being that there was no assembler or hardware for loading the finished code!
The machine in question was a label application tool for a production line. You know, product goes in bottle, label gets slapped on the side. But the slapping needed to be perfect because consumers shy away from packaging that looks shoddy. Computer control would end up being far superior than the mechanical means the factory had been using because it simplifies the ability to adjust calibration and other parameters. [John] started from square one by interfacing the KIM-1 with the existing hardware. It has a hex keyboard which is how the program was entered into the device. But first he wrote the software on sheets of notebook paper like the one seen above. It includes his hand assembled code, which was then typed in on the keypad. Kind of makes you appreciate all the tools you take for granted (like Eclipse), huh?
Filed under: Software Development
[Lee Davison] acquired an Acer laptop that didn’t have a display anymore. He had enough parts on hand to add in an LCD panel and give it a CCFL backlight. But when he started looking for an inverter to drive the backlight he couldn’t find one. What he did have on hand were some smashed screens that had LED backlights and so the CCFL to LED backlight conversion project was born.
He tore into the LED display and found the driver board. Unfortunately he didn’t locate the datasheet for the exact LED driver, but he found one that was similar and was able to trace out the support circuitry on the PCB. This let him cut away the unneeded parts of the board without damaging the driver. He didn’t want to pull out the CCFL tubes until he was sure the LED conversion would work so he tried it out on another smashed panel (where does he come up with all these parts) and it worked great. Once he got everything in place he was very happy with the results. The only drawback to the system is that he doesn’t have the ability to dim the backlight.
Filed under: repair hacks
This robot doesn’t know if it’s a walker or a tank. It’s the brain-child of [Marc Hamende] who works as a mechanical engineer by day and mad roboticist at night. The best place to find full details is by digging into the long thread he’s been posting to for about six weeks. It will give you a pretty good snapshot of his approach, starting with SolidWorks renderings of the project, and adding in assembled components as he brings the project together.
The mechanism for each foot is fascinating. He milled the white pieces which stack together to encapsulate the motor that runs the treads. These assemblies pivot to bring the metal rod serving as a walking foot in contact with the ground. But they also make it possible to adjust the treads to deal with rough terrain. A Propeller chip drives the device, with an Xbee module to communicate with the controller.
Don’t miss the video after the break. You’ll hear some skidding as it makes turns, but [Marc] plans to add code to adjust motor speed in order to compensate for the inside/outside differential issues. He’s also posted an image album over at Flickr.
Filed under: robots hacks
When you want to print a 3D object you run into problems if there is a part that has nothing below it. The hot, soft filament coming out of the extruder will droop with gravity if not given something to rest on while it hardens. The solution is to use a second material as a support. But then you’ve got to find a way to remove the support structure when the printing is done. That’s where this beauty comes in. It’s a heated stir plate for dissolving PLA.
The PLA is printed using a second extruder head. Once the part is cooled [Petrus] puts it into a heated bath of sodium hydroxide (lye). The solvent will remove the PLA but not harm the ABS. Speaking of ABS, [Petrus] also mentions that this can double as a temperature controlled hot plate for polishing ABS prints using acetone vapor.
There’s all kinds of good stuff inside of this beast so do check out the full plans to learn more. Our favorite part is the stir bar which is a piece of threaded rod and a couple of nuts. To make it safe to submerge in the chemicals he 3D printed a pill-shaped enclosure for it.
Filed under: tool hacks
Retro gaming enthusiasts take note: this joystick is what you need to play any Atari game on the original console. It plugs right into the original console hardware and removes the need to choose the joystick, paddle, or keypad controller separately. You just leave this puppy hooked up and move your hands to the set of controls used on each game.
[x2Jiggy] built the thing from scratch. The enclosure is a wooden box from the craft store. He holds it closed with a couple of magnetic latches like you might find on old fashioned kitchen cabinets. The buttons of the keypad are mounted on a chunk of protoboard but he did take the time to give it a coat of matching paint so that it doesn’t look out of place. Inside you’ll find some more protoboard and point-to-point soldering to complete the rest of the connections.
You can see a fast motion video of the build process after the break. This reminds us of the universal controller built for Project Unity.
Filed under: peripherals hacks