360 Servos

[m0rph3us]

Has anyone seen servos that can rotate 360 degrees and where I can buy them? Because the ones with EduRobot only turn about 270.

[Dung H Cao]

Try modifying the servo yourself
http://www.fortunecity.com/marina/ne...Bas_360_R.html

or purchase at
http://www.hobbyengineering.com/SectionM.html

I don't think either of these options will meet 2004 Robot rules.

Good luck

[GregT]

Originally Posted by m0rph3us

Has anyone seen servos that can rotate 360 degrees and where I can buy them? Because the ones with EduRobot only turn about 270.

While such servos are made, FIRST restricts us to what came in the kit of parts. If you only need one 360 servo you could mount a servo on top of another servo which would give you twice the rotational range.

If you wish to use a servo as a speed controller / motor all-in-one and it's not for a FIRST application, you can modify the edu servo(s).

If you want to do something similar to what was shown at kickoff by the IR tracking bot but have a wider range of sensor vision you will probably have to build your own servo (unless they put a stepper motor in the kit this year, I haven't looked through one yet).

If your team is in possession of a talented programmer you might try attaching a rotational encoder to a motor driven shaft. This will allow you to turn the shaft (through the motor) and sense how much the shaft has actually rotated (by counting pulses from the rotational encoder). Note that a rotational encoder (mechanical or optical) will send a pulse to your robot controller X times every revolution (some pulse every 25 deg., some every .1 deg.). This approach would allow you to detect the angle your shaft has turned over a unlimited range of rotation.

You could also use a variable resister to accomplish this, just like the servo in the kit of parts, but the variable resister would have a limited range of rotation, just like the one in the kit of parts.

Hopefully at least something I said made sense.
Greg