Cheap XY Table Using Hobby Servos

[CarlS] wanted to build a low cost x y table for display on teletoyland.com. He realized that to keep cost low, he could use hobby servos instead of stepper motors. Exact precision wasn’t a big issue here, so the hobby servos would be perfectly acceptable.

Though Linear hobby servos are available, he decided that the cost was prohibitive.  He used normal hobby servos, but had to modify their internals to get the exact amount of travel necessary. Many people modify the hobby servos for continuous rotation, but this would cause a loss in the ability for exact positioning. Instead, he replaced the potentiometer that measures the position of the servo with a 10 turn potentiometer. This allowed him 10x the travel.

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Build A ROBONOVA-I


On the latest episode of Systm, they talk to [David Calkins], founder of the RoboGames competition, about humanoid robotics. The robots featured in the episode are Hitec’s ROBONOVA-I. The ROBONOVA is about a foot high and has 16 servos with support for up to 24, all connected to an Atmel controller. The episode is quite long: At around 15 minutes, they demonstrate the programming enviroment. You can program it traditionally or pose the bot to work out the motions. At 30 minutes, [David] mentions that next year’s competition will allow airsoft weapons to be attached, but bots have to be controlled from a first person perspective. If you’re interested in one of these kits, they have a ROBONOVA special of $900 or as low as $500 for educational institutions (that’s us, right?). Now is the perfect time to get one since you’ll have nearly a full year to prepare for RoboGames.

Related: You’ll hear builder [Matt Bauer]’s name mentioned several times.

[via BotJunkie]

Turn Any Motor Into A Servo With RepRaps New Board


[Zach] just let us know about a new board that’s available from the RepRap project. It uses an AS5040 magnetic rotary encoder to measure the absolute position of the rotor of whatever motor you’re using. This is actually pretty damn exciting. Powerful servo motors are expensive, but with one of these, you can use whatever motor you can get your hands on. Big DC motors are cheap, but even used DC servo motors expensive. Best of all, the encoder is open source and you can score a kit version for a paltry $20. Now we can make that 8 horse power servo…

Modifying A Servo For Continuous Rotation

[robomaniac] shows us how to modify a standard servo to allow continuous rotation. This is a classic robotics hack and has been around for a while, but we really like the way he put this together. Although you may need some soldering and desoldering tools to open the servo up, the hack is a physical one. All you really need to do is cut off a plastic tab on one of the gears. If you want to see an example of a bot you can build with one of these CR servos, he just posted this one motor walker.

Intervalometers And Timelapse Photography


Time lapse photography can seem out of reach for many of us who don’t have fancy cameras(or a hacked cannon point and shoot). We recently covered using a TI-83 as a timer, and now we’ve gathered a collection of DIY intervalometers to help you get clicking.

Up first, for those of you who don’t want to dismantle your camera, here are some mechanical ones that will work on any camera.

[Simplesimon] has done a fantastic job with this integrated system pictured above. He’s added an adjustable solenoid to click the shutter release. By including a second kit board to handle an RF remote, it has remote single shot capabilities too!

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Pulse, The Emotional Visualization Organism


[Markus Kison] built a device called Pulse, which is part art installation and part data visualization tool. What the emotional visualization organism called Pulse actually does is scan new posts on Blogger.com blogs for synonyms of keywords related to 24 distinct emotions from eight emotional groups. A red cone in the center expands when keywords are detected, in effect acting as a mood indicator for Blogger.com blogs.

The 24 distinct emotions are based on [Robert Plutchik]’s psychoevolutionary theory of emotion, and the device itself is built from a glass case, various servo motors, and custom controller for the servos. This is a compelling idea, but we wonder whether it scans for modifying words or just the keywords alone. It wouldn’t make a lot of sense to have the sadness region expand drastically if many people simultaneously post the sentence “I’m not sad at all.” Video embedded after the break.

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