Limor a.k.a. Ladyada has been a long standing staple in the Hack-A-Day community and we were more than happy to hear about her latest project. The Minty Boost is an improvement on the idea of building a battery powered USB charger. Most designs (including ours) use a 7805 linear regulator with a 9V battery. Even in the best case the regulator is only about 60% efficient which means you’re losing at least 1/3 of the power to heat. Limor’s design is a much more efficient boost converter design and uses far more common (and rechargeable) AA batteries. She’s got a thorough write up on how to build the converter in an Altoids gum tin. The end result is 82% efficient and can effectively double the play time of a video iPod.
The guide doesn’t end there. Limor actually wrote this as a demonstration on what goes into a making a kittable project. She covers the entire process from component selection, to mass PCB production, to what her final cost break down is. The guide is full of pictures thanks to some good planning as well. Of course the most interesting thing we learned from the guide is this: despite using the tins all the time, Limor finds the taste of Altoids gum disgusting.
[The guide is on her site, but we’re linking to the version on Instructables since we’ve managed to DDOS her site in the past… by announcing that her site was back online.]
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Hack247 has posted their first project: a portable media center extender. It has a wireless video sender that’s connected to an Xbox running XBMC. The receiver is housed in a box with the popular Sony PSone LCD. The box can transmit remote commands back to the Xbox for full control. It’s a nice bit of kit, but he still needs to build the battery pack.
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My buddy Willy Volk at Divester has always been good about passing along stories about cool remote operated vehicles and this is no exception. A team of 8 engineering students at RIT have built an ROV capable of diving to 400 feet. Most schools design there ROVs for competition in pools, but the RIT seniors had a real-world goal: exploring shipwrecks in Lake Ontario. They built a lightweight aluminum frame and mounted batteries onboard. The ROV moves via four commercial thrusters controlled by an ATMega128. There are 3 video cameras plus HID lights. All control comes from a laptop using an RS-232 tether. More details are provided in their conference paper PDF.
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Drew and Calvin built this DDR whack-a-mole game for their EECS 373 class. It’s powered by a Freescale MPC823. The processor controls eight servos with pictures of their friend Malav. The game runs for 20 seconds and then reports how many Malavs you’ve stepped on. They say that the hardest part of this project was figuring out how to properly read the Playstation DDR pad.
[thanks Ano nym ous]
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We’ve covered the toner transfer method for creating circuit boards before. Instead of using an iron, Rich uses the fuser out of a laser printer to get consistent results. He wired a dimmer to the power supply to regulate the temperature. The fuser has a built in thermistor, so you can read the temp using an ohm meter. For rate control he built a stepper controller that connects to a parallel port. Using a simple program he’s able to control both speed and direction.
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[Jussi Saarijoki] had a broken LCD monitor and decided to use it as a photography light instead of letting it sit on his shelf of “oblivion”. Only the panel was broken; the cold cathode and diffuser were still intact. He stripped off all of the outer casing and pulled the broken panel. After reassembling he did a couple test shots. The large panel works really well for providing ambient light and making shadows a lot less harsh.
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Feeling a bit nostalgic, reader [blurry] decided to write this Apple Game Server in Java using the rxtx library. The server eliminates the need for a floppy drive on your Apple //. You just need to connect the Apple // to your computer using a null modem cable and you will have access multiple games. To get started you tell the Apple // to accept serial commands. Then the Java program takes over, typing the loader program one line at a time. It takes about 15 seconds. Once that’s done you’re presented with a menu to boot whatever game you want.
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