[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.
[Ammon] repairs busted LCD monitors as a side hobby, so replacing burned out CCFLs and inverter circuits is something he can do in his sleep. One Dell monitor he received had him so perplexed, that he simply gave up on trying to repair the inverter circuit. He still wanted to get it working, so he had some narrow PCBs made and started working on his LED replacement backlight.
He built a driver board for the LEDs, populated with left over components that he stripped from the LCD panel’s inverter circuit. He needed space to insert his driver board, so he simply cut out a chunk of the inverter board and slipped his replacement driver board in its place. As you can see in the picture above, his board (in green) takes up far less space than the original inverter circuit it replaces.
He provides a schematic for his circuit as well as a PCB layout file, so it should be fairly easy to replicate his work. He has not posted schematics or layout information for his LED strips, but we’re betting he will if someone asks nicely.
Check out this pair of posts if you are interested in reading more about replacing your burned out CCFL with LEDs.
[palmertech] and [Bibin] have both completed backlight projects for the Game Boy Pocket recently. The most difficult part of the transplant is carefully removing the reflective backing on the LCD. After a thorough cleaning, a diffuser and backlight panel were added. [palmertech] used a backlight salvaged from a DS, while [Bibin] built his own using LEDs. You can see his backlight in the video embedded below. There’s a disassembly video too.
Continue reading “Game Boy Pocket backlight”
We’d never discount the beauty that is the SpokePOV bike wheel kits, but if you want to just turn your bicycle into a blinding blur, [depotdevoid] has the solution for you. He had a CCFL tube left over from an abandoned LCD monitor backlight repair, and decided to see what it would look like as a wheel light. The result turned out fairly well. He had to figure out how to mount the 8 batteries plus step-up board. He says the extra weight isn’t really noticeable and the light output is quite bright. CCFLs can be incredibly fragile, so take care when you do the actual mounting.
We’ve seen some fairly impressive mixer projects this year, and the Aurora mixer is no exception. It is a dual channel USB-powered mixer with two linear faders, one crossfader, eight backlit buttons and 24 potentiometers, all built around a PIC 18LF4525 microcontroller. That’s all pretty typical for a mixer, but this one is very visually attractive, featuring a clean and stylish form factor and controllable lighting both under the board and in the LEDs backlighting the buttons and knobs.
Whether you want to buy one now or build one yourself, the Aurora team has made both possible. You can contact them for pricing if you are ready to buy. If you prefer to build, this is an open source project with full assembly instructions, schematics, drivers, patches and all other source code and information you should need available here. See more photos of the Aurora mixer here, or see it in action after the break.
Continue reading “Aurora open source hardware mixer”