R/C airplane motors from computer trash

Here’s something that the R/C airplane crowd might think of as old news. These directions show us how to rework floppy drive and CD Rom motors to be high power airplane motors. There are several listed, with details on each, but those unfamiliar might want to start with the most basic CD Rom version. It covers winding your own copper and installing the magnets in the “bell”, putting it all together and mounting it. This is a great writeup for those who haven’t seen this done before. If you want something even simpler though, you might enjoy the homopolar motor post. If you’re more advanced, they have tips for you too on machining and balancing the motors as well as winding density.

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Omni-car

We stumbled onto one of [Nik Melton]’s projects, an Omni-car. It is omnidirectional, meaning it can go any direction at any time without having to turn. The body was designed by him, then printed with a 3D printer. The control scheme is what interests us though. He has found a simple way to wire it to get the job done. Sure you can see that it suffers from some pretty bad “drift” when trying to go in a straight line, but overall, we think he pulled it off well.

You might want to take a few moments to look around his project page. This guy has done a bunch of fun stuff like delta robots, strange hybrid wheel/leg robots, tesla coils, and arm mounted flamethrowers. Judging by the videos, he’s pretty young too. We think his guy has a bright future ahead of him.

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RFID door lock – the right way

[Pcmofo] has shared a well-built, well-explained example of how to implement an RFID key system for a door. We call this the right way because it is well thought out and functional. In the past we’ve seen doors that unlock via a secret knock, keypads, and RFID, but they are all non-permanent solutions capable being transplanted from one door to another. Rather than building a mechanism to turn the door handle, this implementation uses an electric strike mounted in the framing of the door to allow access. These are used for security doors in buildings and are built to keep your door secure.

The hack in this case is the electronics. Using an AVR ATmega168 running the Arduino boot-loader, [pcmofo] has prototyped a two-part design. An RFID reader is mounted outside the door with data wires running to the inside where the microcontroller resides. A hard-coded RFID card is used as a “master” to train any number of tags for entry. The master puts the device in training mode and the next tag to be read is added to the list of tags authorized to open the door.

We like messy wires and quickly thrown together devices but this is built to last and will look great once mounted in an appropriate enclosure.

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Rotating radar visualization

We ask, who wouldn’t want a rotating motion and distance tracking radar? Sure in today’s day and age anyone could purchase a wide-angle sonar or IR solution that achieves the same goal, but [LuckyLarry] took it old school and made his own rotating radar. He used an Arduino, servo, and ultrasonic sensor as a base to gather data, and the open source programming language Processing to draw the data on the screen. He says it’s a little inaccurate currently, but will try out some other sensors in the future.

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USB to serial adapter

[Spikenzie] is at it again. This time he’s posted a nice USB to serial converter. He points out that you can buy a USB to serial adapter pretty cheaply, but sometimes you want this functionality built into your project enough to justify the greater cost. In those cases where you want to integrate it, this is an elegant solution. This design was made to be fairly compact and still usable on a breadboard. As usual, you can download the files from his website. If his work looks familiar, it’s because we’ve covered his work several times before.

[via Flickr]

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