Author: Eliot

1332 Articles

RFID Enabled Deadbolt

May 8, 2006 by 25 Comments

rfid door

We saw Amal Graafstra, the author of RFID Toys, at Maker Faire. Even though we spent most of the time at his booth poking at the RFID tags embedded in his hands we did remember him mentioning that he would be releasing a free bonus chapter. The first chapter of the book shows how to connect an RFID reader to your home automation system for front door access control. The free bonus chapter describes how to build a standalone system for operating a single deadbolt. The Powerbolt deadbolt he chose makes this project pretty easy since it already has marked solder pads for open and close. A BASIC Stamp 2 is used to read the tags and operate the lock.

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Bluetooth A2DP Speakers

May 7, 2006 by 20 Comments

bluetooth speakers

[Simon Elkrief] was tired of waiting for manufacturers to produce a set Bluetooth stereo speakers so he built his own. Stereo over Bluetooth is handled by the A2DP profile which isn’t very common. Simon had to perform a registry hack to activate it on his HTC Wizard. OS X still doesn’t have support for it. He used the Bluetooth receiver out of a pair of broken Logitech headphones and wired it directly to a set of powered speakers. Now he can stream stereo sound from his phone to the speakers. He plans on developing an even better set in the future.

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Microcontroller Design Final Projects

May 6, 2006 by 10 Comments

hard drive clock

Bruce Land let us know that the final projects for EE476 Microcontroller Design, a class he teaches at Cornell, are online now. You may remember some of last years projects: P-P-P-Palm, Big Red Juice Mixer, wireless telemetry. This year’s projects include a Reflow oven controller, an RFID security system, and an autonomous helicopter plus many, many, more.

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ITrip Mini Universal Mod

May 5, 2006 by 10 Comments

itrip mini

[josh mason] is in the process of converting his iTrip mini FM transmitter (cache) so that it will work with any device. The iTrip uses the iPod’s accessory port for power and control. The acc. port is what Apple used before settling on a standard dock connector. After he cracked open the iTrip, Josh compared it to an earlier hack we featured and noticed that the wiring was backwards which explains why the acc. port devices won’t work on different generations. He’s got a new headphone jack attached but still needs to construct a power supply. If he wasn’t making the device universal, he could get 3.3V out of his nano’s dock port.

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Luxeon LED Bike Headlight

May 4, 2006 by 15 Comments

luxeon headlight

[Ian] built this headlight for his commuter bike. It is based around the Luxeon Star LED which is supposed to be equivalent to a 5W halogen. He mounted it to an aluminum frame and used a Fraen narrow lens. It’s powered by a pack of 4 rechargeable AA batteries. He’s got a list of improvements he would make. The first one is a better casing since his looks terrible compared to Suzy Jackson’s sexy light.

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Smart Wheely

May 3, 2006 by 17 Comments

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

May 2, 2006 by 9 Comments

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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