Smart Wheely

electric unicycle

I found this self-balancing unicycle via Trevor Blackwell’s site. Dr. Hofer’s self-balancing unicycle uses a wide tire for lateral stability. Trevor had spent several months learning how to ride a unicycle before building his; the large tire makes the learning curve for this one a lot less severe. The project site is in German, but I found one write-up in English. The majority of it is dedicated to the control scheme. It is very difficult to model the unicycle as an inverse pendulum due to so many unknowns. Dr. Hofer’s team used fuzzy control instead which let them apply several layers of rules without requiring a lot of previous knowledge. Here’s a photo gallery of the device.

[sean] reminded me that I forgot to include the obligatory link to Bombardier’s Embrio concept.

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Computer Controlled Balsa Router

computer controlled balsa router

As a follow-up to yesterday’s post, [owen] sent along a link to his computer controlled router table for balsa cutting. This was his project before switching to lasers and sheetmetal. The write up starts with an interesting discussion about CNC not really being a magical tool or time saver. Sure, it can be pretty quick about cutting accurate pieces, but you still have to assemble it. Most likely all of the time you saved cutting was spent designing and prepping, which you could have spent cutting accurate parts by hand. Owen had extra time to spend designing since he was traveling for business. He does admit that the ability to quickly generate replacement parts has made him a more courageous pilot.

Other gems from yesterday’s comments: CNCZone is apparently the one-stop shop for all of you CNC hobbyist needs. [javamoose] pointed out that he’s nearly done with his scratch built CNC machine seen on bit-tech. [mike]’s FIRST robotics team is in the process of converting a punch tape driven Bridgeport NC mill. They found the owner of wimb.net very helpful. [ivan256] recommended the plans found on John C Kleinbauer’s site.

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Team Hack-A-Day CNC

team hackaday dxf

The Team Hack-A-Day forum recently started a thread to discuss homebrew CNC. Computer Numerical Control machining is a very popular topic in our community because of the prohibitive cost of buying a machine off-the-shelf. Searching through the archive it seems we’ve only covered one actual CNC machine; since people have been building these things for so long, it’s hard to come up with the definitive CNC project. We’ve also featured the Etch CNC, designed by the AXIS developers to verify their software.

My coworker Will O’Brien, who writes how-tos for Engadget, recently started working on a new CNC mill. You can expect a write-up on that in the future. Also, Lady Ada recommends Drill Bit City for sourcing cheap carbide bits.

If there is enough interest, Team Hack-A-Day might add another forum for CNC projects.

For those who don’t know: Team Hack-A-Day was founded by Hack-A-Day readers to support our Folding@HOME efforts. Through their work we are now the #37 team (and still gaining) having produced nearly 20 million points in the last 8 months.

[thanks Tired2, op for #hackaday on EFnet]

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Portable Magnetic Card Reader

portable magnetic card reader

[ned]’s HandySwipe is a portable magnetic card reader. It runs on 4 AA batteries and collects data from track 2 cards. It uses a PIC 16F688 and displays the card’s data on a small LCD. It can store up to 50 cards and dump them in CSV format. It will also output the raw bitstream for use with Acidus’s StripeSnoop. Ned’s project write up is pretty interesting since he covers using a logic analyzer while swiping a card and driving the LCD with only three pins using a shift register.

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