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Electronics => Electronics => Topic started by: JAy1st on April 23, 2008, 03:03:32 AM

Title: Modded servo with position feed-back
Post by: JAy1st on April 23, 2008, 03:03:32 AM

Hi all,

Has anyone ever heard of modding a servo to get position feed-back ?

I mean, when you tell it to go in a certain position, you have no way of know it's really where you want it, right ?

So what about connecting a wire to the center pin of the pot (inside the servo to make a Voltage divider) and read it's analog value do know the real position?

Will it mess up with the electronics driving it or not ?

Ideas are welcome !

Title: Re: Modded servo with position feed-back
Post by: paulstreats on April 23, 2008, 04:11:01 AM

google "open servo". Open servo is a project which does just this and more with servos.

You can try wiring straight to the pot, but do it in such a way as to be able to remove it easily because you may cause too much noise on the wire which will give the servo circuit false readings (try a low power small signal diode stright on the poit and a wire from that)

Title: Re: Modded servo with position feed-back
Post by: airman00 on April 23, 2008, 09:30:12 AM

Quote from: JAy1st on April 23, 2008, 03:03:32 AM

So what about connecting a wire to the center pin of the pot (inside the servo to make a Voltage divider) and read it's analog value do know the real position?

Will it mess up with the electronics driving it or not ?

sure that will work , I think I've seen people do that before

Title: Re: Modded servo with position feed-back
Post by: JAy1st on April 23, 2008, 09:42:18 AM

I've seen open servo before, it's great and too expensive for a basic type of guy like me  ;D

Quote

sure that will work , I think I've seen people do that before

Have any references ?

Title: Re: Modded servo with position feed-back
Post by: airman00 on April 23, 2008, 09:53:16 AM

Quote from: JAy1st on April 23, 2008, 09:42:18 AM

Have any references ?

Sure

http://www.seattlerobotics.org/encoder/200101/EncoderPos.html

Title: Re: Modded servo with position feed-back
Post by: JAy1st on April 23, 2008, 12:14:50 PM

Not really the same.

That servo is fitted by standard with 4 wires....but gives a hint on what can be done..

Tnx for the link....

Title: Re: Modded servo with position feed-back
Post by: airman00 on April 23, 2008, 12:27:29 PM

well it will work for all servos , that was just an example

logically, it should work without disturbing anything

Title: Re: Modded servo with position feed-back
Post by: Admin on April 26, 2008, 06:50:45 PM

I've seen it done too, just use an ADC on the pot value.