Robot Fish CAD Models

November 2, 2008 by Eliot 4 Comments

[Bre] dug up this excellent robot fish prototype project. The PPF-O9 has three servos. One on the forward fins to control depth, one on the middle joint, and one final one drives the tail fin. The battery box is mounted to the underside. The control scheme is interesting: the right stick controls left/right and up/down while the left stick controls the frequency and amplitude of the motion. They say the robot is fairly stable, but swimming and turning can be slow. They’ve included CAD files for almost every component to help you with your own designs.

In June, we highlighted a robofish designed for swarm communication.

Six Legged Crawler

November 1, 2008 by Jason Rollette 6 Comments

This hexapod was sent to us on the tipline from [Jamie]. If you want to take the six-legged robot a bit farther than our earlier posts, here and here, this is the hexapod for you. The structural pieces were modeled, and cut out of 3mm thick plywood using CNC. He used TO-220 transistor nylon isolation mounts for the bearings, and bolts and locknuts at each joints. The main body houses eight servos, six for the legs and two for a camera head pan and tilt. There are another six servos, one for each leg, to lift the feet. The whole thing is controlled by an Atmel AT90S8515 clocked at 8 Mhz. The code was compiled using WinAVR free GCC GNU-C. He uses a PlayStation controller to help debug the walk cycles, and change parameters as needed. Watch a video after the jump.
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Cheap XY Table Using Hobby Servos

September 30, 2008 by Caleb Kraft 6 Comments

[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

July 23, 2008 by Eliot 14 Comments

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

July 16, 2008 by Will O'Brien 20 Comments

[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

July 14, 2008 by Benjamin Eckel 7 Comments

[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

July 9, 2008 by Caleb Kraft 6 Comments

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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