[Marcus] sent in his work on making ECGs. His first one was inspired by [Jason]’s. Believe it or not, you can build this thing for under $5. After getting it semi-functional, he decided to pick up a cheap one and mod it for PC input via the sound card. (There are plenty of sound card oscilloscope projects that will work for this.) Remember kids, don’t go sticking electrodes on anyone unless you know what you’re doing: correctly placed electrical shocks (even low power ones) can be deadly.
diy448 Articles
LCD Projector Repair
[Kieth] picked up an Infocus projector only to find that it needed some repair. The polarizer on the blue light path was toast. When he parted out an Optoma projector he scored a polarizer that was just about right for the repair. It’s a good read even if you don’t have a projector in pieces at the moment. He ended up bending the mounting bracket a bit to hold the filter and got his projector fully up and running again.
Projector Hacks Roundup
Projectors have long been a favorite toy of hardware hackers. From reactive displays to cheap home theater, there are plenty of reasons to play with photons. Seeing some cheap projector repair put us in the mood to cover some of our favorite projector projects – check em out after the break.
Cheap Projector Repair
[Ryan] sent in this writeup on some DIY projector repair. The write-up is a little hard to follow, but maybe it’ll inspire some future projector landfill saves. [Dissident] replaced the light bulb and ballast in an older DLP projector with some salvaged MR-16 hardware from an even older over head projector. The main trick required was to bridge the trigger leads that tell the projector that the bulb is on and working.
DIY Heated Vest/clothing
[Jared] sent in his experiment in building his own heated vest for motorcycle riding. He used some of the ever so common enamel coated wire and some surplus teflon tape in place of Teflon coated wire. So far he’s been testing things out with a bench power supply, but it seems to be working. Despite my love of building my own stuff, I’d probably just pony up for a commercial product. His site is hosted on his DSL, so I’ve put up a mirror here. (with some tweaks to the thumbnails to make them load faster.)
DIY CD Changer
[nophead] put this creation down to its final resting place, but it still deserves some attention. A Motorola MC6809 ran the show while a stepper driven robotic arm tipped with a suction cup fetched the selected disc. [nophead] has an interesting blog covering his work on building a 3d prototyping machine. The goal is to use it to produce a reprap, but he does a nice job of covering design problems and his attempts to solve them.
DIY Home Theater Preamplifier
[Dane] built this excellent home theater pre-amplifier. He used [Mark Hennesy]’s pre-amp design to start with, and added selectable XLR, RCA, SPDIF and even USB audio inputs. Discrete inputs from his DVD player provide surround input, and an analog matrix creates 7.1 surround from the 5.1 input. The design is very elegant, and even uses a VFD display that appears blue with some filters. I usually just buy my HT gear, but projects like this make me seriously consider re-building my entire HT from scratch.
