Author Topic: servo calibration  (Read 3385 times)

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Offline amandeep1Topic starter

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servo calibration
« on: November 30, 2009, 07:00:14 PM »
hey i followed this tutorial to modify my servos

http://www.kronosrobotics.com/an116/GAN116at.shtml

i am at the last part to calibrate them however i am confused. i just put random code in arduino to make it spin 360 degrees front and then go back and repeat. then i kept moving the pot until it stopped moving. did i do this right? what is the purpose of calibration?

thanks and sorry if this is dumb question i am beginner  ;D

Offline Gertlex

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Re: servo calibration
« Reply #1 on: November 30, 2009, 10:34:36 PM »
The point of calibration is to set the servo such that it doesn't rotate when at the centered position (127 on a 0 to 255 bit range, or 1500s).  That way, you always know what value to send via code to stop the servo.

So put code into the arduino that would center an unmodified servo.  With this signal being sent to your modified servo, it will rotate if the potentiometer is not in the centered position.  The servo uses the potentiometer to judge the position.

Hopefully that explains it well enough.  I could explain more in depth how the potentiometer position is "judged", but that's not needed at this point, I think.
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Offline amandeep1Topic starter

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Re: servo calibration
« Reply #2 on: November 30, 2009, 11:16:59 PM »
ok thanks so if i am using the servo library for arduino

Quote
myservo.write(127);

should work or do every servo have a different position center position?


also i don't want to make a new topic so i will ask here. are there good tutorials or guides to make a 5v regulator.

Offline Soeren

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Re: servo calibration
« Reply #3 on: December 01, 2009, 09:34:23 AM »
Hi,

ok thanks so if i am using the servo library for arduino

Quote
myservo.write(127);

should work or do every servo have a different position center position?
If you output the 1.5ms pulse, you can adjust any servo to stop, to make them alike (no guaranties for the extremes though).


also i don't want to make a new topic so i will ask here. are there good tutorials or guides to make a 5v regulator.
You're thinking of using a 5V regulator (the ones that the IC manufacturers make), right?
Or do you want to make a regulator from discreetes/op-amps and such (that's not a subject for a beginner)?
Regards,
Sren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline amandeep1Topic starter

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Re: servo calibration
« Reply #4 on: December 01, 2009, 06:34:57 PM »
sorry meant using

any suggestion?

Offline Gertlex

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Re: servo calibration
« Reply #5 on: December 02, 2009, 09:59:38 PM »
If your servos get damaged by being held against turning or some such, you can end up with some that don't center properly.  For example, I have a used metal geared servo that I got off ebay that doesnt' center properly :/

But ya, that's just trivia at the moment.

(Can't help ya on 5v regulators)
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Offline amandeep1Topic starter

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Re: servo calibration
« Reply #6 on: December 03, 2009, 08:16:40 PM »
how are you guys powering the servos?

 


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