Open source motor controller

The OSMC project was started in 1998 to provide a high quality H-bridge speed control to hobbyists and professionals. The original design was intended to be used by people who were building Battle Bots and other competition robots, but the line has expanded since then. The project embraces the open source spirit by making the plans freely available and encouraging modification. This is the same controller that Trevor Blackwell used in his Electric Unicycle.

[thanks monster]

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Magellan eXplorist upgrade


This Russian site has all the details needed to upload new maps to a Magellan eXplorist 300, 200, or 100. Inside the battery case are four pads that can be used for serial communication. You will have to use a MAX232 to shift the voltage levels. Since this occupies the battery space you’ll need to provide power as well. This can be tapped from a USB port. Once the cable is built you can download waypoints using OziExplorer.

[thanks Chris, Cary for corretion]

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Printed circuit board etching


This isn’t meant to be the definitive PCB etching post. I don’t have any experience etching boards and was hoping readers could contribute their best/favorite methods for etching boards in the comments.

We’re linking to Tom Gootee’s page on toner transfer etching. The first step is to print the design on glossy paper using a laser printer. An iron is then used to transfer the toner to a prepped copper board. The board is then soaked in etchant to remove the exposed copper. The printer toner is mostly plastic and resists the etchant. Once the board  is etched, Acetone is used to remove the toner. Tom has been keeping his site up to date and as his research progresses.

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Tempest for Eliza


Tempest for Eliza” is a program written by Erik Thiele to demonstrate the RF transmission properties of CRT monitors. The program is capable of transmitting sound over AM frequencies just by the unique way it drives the monitor. The electromagnetic emissions of CRTs can be a security problem as demonstrated by Van Eck phreaking, watching someone’s screen just by collecting RF transmissions. In the late ’90s Ross Anderson developed software to help reduce the RF transmissions of monitors. These specialized fonts combined with shielding can greatly reduce the risk of attack and is something the NSA has been researching for many years.

[thanks gsham]

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Disco dance floor roundup

disco dance floor

Probably the most popular project this summer was the MIT Disco Dance Floor. The build team eventually released the controller schematics and software. Several other projects spun off as a result of this.

We’ll start with the Disco Bar (since it has the most pictures). David has been actively building the bar and is nearing the finish line. He built a bar instead of a floor because as a white guy from  Wisconsin, he’s a far better drinker than dancer. I tend to feel one leads to the other.

David’s project is driven by software that Washington University students developed while building their Vertigo Dance Floor. The software includes a cool utility for building animations.

Also: Monkey see, monkey build and Tom’s Blog (in German)

[Update: We forgot to include the DECT phone system controllable Disco Dance Floor by Blinkenlights at 2005’s best hacker camping extravaganza, What the Hack. Another pic by an attendee of wth is here.]

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Arcade game chair

arcade chair

[Chuck Cage] and friends have been building a variety of arcade racing platforms. The third version, pictured above, has a real racing seat and can support a 32″ television. They’ve got advice for navigating the local “you-pull-it” when buying seats. There are material and paint selection tips on the site as well along with pictures of their three different versions.

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iPod breakout dock

breakout dock

Since the time it was first featured on MAKE, Steve Chapman has continued to develop his iPod breakout dock. The dock provides all of the possible connections that could be made through the 30-pin connector. Of interest is the iPod’s serial interface. I had seen a break down of the control codes before, but Steve has taken the time to develop a serial application that he can use to test the different commands. Now that he knows a little more about the interface he’s started programming a microcontroller to use it.

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