Make An ECG With Your Sound Card


[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.

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.

Metalab’s LED Matrix Display


Our friends at Vienna’s Metalab have been working on this project quite a while. Soldering their hearts out to create an FPGA controlled monochrome LED dot matrix display. It’s 48×72 array totaling 3,456 LEDs, soldered by hand. It creates some serious geek bling thanks to an mplayer plugin developed just for the project and it runs up to 72fps. Build details and source code are on the project page. Be sure to check out the awesome video demo below.

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PIC Controlled Spray Paint


Most people make LEDs light up for their first microcontroller project. [Alex] built a “large scale dot matrix printer.” This beast is a PIC controlled ground graffiti machine. As it rolls across the ground it deposits strategically located bits of spray paint. Rather than use actual spray paint, he opted for a set of solenoid controlled nozzles that shoot the paint downward.

Lumenlab’s New Kit: Open Source CNC


Imagine our surprise when we stumbled on the latest Lumenlab project: gantry style CNC. Until now the only time we ever invoked their name was for DIY projectors. The kit looks pretty interesting, and they’re taking pre-orders right now. It’s designed for a full sized router and you should be able to cut a 4′ by 8′ sheet with a feed roll. Even without, the cutting area is a large 26″ by 50″ and features 8″ of Z movement. Between their kit and an order from Online Metals, they’re projecting that you can build your own for around $1000. We’re definitely in when the final kit is released in June.