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Topic: setting an angle on a continuous rotation servo (Read 2 times) previous topic - next topic

Ro-Bot-X

Since no one gives an answer to the question of the topic, I have to step in and show you some methods to hack a servo to get both regular and continuous rotation:

1. Replace the electronics in your servo and get full positional control. The perfect solution, but costly:
http://letsmakerobots.com/node/18615
Nowadays you can buy digital servos that already have built in these electronics.

2. Modify your servo for continuous rotation as usual, then open up your potentiometer, cut off the stop, then add a transistor triggered relay that replaces the potentiometer with 2 resistors; use a separate wire to trigger the relay to turn your servo into a continuous rotation servo or a regular servo:
http://letsmakerobots.com/node/24705

I hope these links will help other people that are looking to use a servo in both rotation modes.

zoomkat

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Since no one gives an answer to the question of the topic, I have to step in and show you some methods to hack a servo to get both regular and continuous rotation:


Good answer, but you did not answer the OP's origional question below:   ;)

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Can you do this with a continous rotation servo?  ...tell it to turn to 45 degrees and stop there for instance? 
Consider the daffodil. And while you're doing that, I'll be over here, looking through your stuff.   8)

Ro-Bot-X

#17
Mar 02, 2011, 01:26 pm Last Edit: Mar 02, 2011, 01:35 pm by Ro-Bot-X Reason: 1
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Good answer, but you did not answer the OP's origional question below:    

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Can you do this with a continous rotation servo?  ...tell it to turn to 45 degrees and stop there for instance?


Actually, both methods allow that. Any unmodified servo is capable of going to 45 degrees and stay there if you continue supplying the pulses for that position. It will not stay there by itself.

With the first method I showed, the servo has a 360o magnetical sensor with a high resolution and it has a built in microcontroller. You can tell the servo to go to ANY position and stay there. Or to just rotate continuously. The way the magnetic encoder works allows the servo to stop at 45 degrees even after a random number of complete rotations.

The second method I showed, is a servo hack, and because of the way the potentiometer is built, you can tell the servo to stop at any degree between about 270 degrees (the range of the potentiometer resistance), for the rest until 360 degrees it is unresponsive. But, there are 360 degrees potentiometers out there (minus about 2-3 degrees), easy to replace the original one. Just look at the video and you will see the servo rotating continuously and then stopping at a certain degree and staying there until a new position was issued.

Of course, if you buy a continuous rotation servo and do not modify it, you can't tell it to go to 45 degrees and stop there!

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