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Topic: DC motor position control using potentiometer - HELP! (Read 4 times) previous topic - next topic

zaciatok

Hello there!
I would like to ask you if there is the possibility to control position of a DC motor using a potentiometer connected to the motor shaft.
Can somebody explain me step by step how to do this ????, it is the first time I'm working with Arduino. I know how a PID controller can be applied.
I have to use the following materials:

DC Motor (7V)
Potentiometer (I can turn it from 0 to 300 degrees)
transistor
diode
resistor
External adapter
Motor shield for Arduino

Please I need your help urgently.
Thank you for reading this message.

JimboZA

#1
Jan 22, 2013, 07:24 pm Last Edit: Jan 22, 2013, 07:34 pm by JimboZA Reason: 1
Why not use a servo?

What you're suggesting is basically what's inside a servo anyway as far as I understand it.

Oh wait, I see you have to use certain materials- is that constraint absolutely fixed? So you're actually building a servo?
Roy from ITCrowd: Have you tried turning it off an on again?
I'm on LinkedIn: http://www.linkedin.com/in/jimbrownza

JimboZA

Quote
Could you help me with this challenge please ???


I think that's beyond my skills I'm afraid.... that's why I buy servos not make them from DC motors  ;)
Roy from ITCrowd: Have you tried turning it off an on again?
I'm on LinkedIn: http://www.linkedin.com/in/jimbrownza

PaulS

What speed does the motor turn at? At 10 rpm, you could read the potentiometer fast enough to stop the motor at a relatively precise location. At 36000 rpm, not a snowball's chance.

fr3dd3v1l

May I know how you control the position?
turning the potentiometer ? or by giving a signal?

zaciatok

The position of the DC motor should be detected by the potentiometer.

PaulS

Quote
The position of the DC motor should be detected by the potentiometer.

You seem to have some bizarre expectation of the potentiometer. The motor could turn the potentiometer as it turns. Then, the potentiometer reading would relate to motor position. If the motor doesn't turn the potentiometer, then the potentiometer won't tell you squat about where the motor is.

You need to answer ALL the questions that are asked of you.

zoomkat

Quote
I think Arduino is not the best way in order to test a control strategy in real-Time


Well, it depends on just what you are trying to do and what your electro-mechanical setup will be. You are somewhat sketchy on how the motor will be operating.
Consider the daffodil. And while you're doing that, I'll be over here, looking through your stuff.   8)

michinyon

Are you planning on gearing this DC motor ?

The problem is,  most DC motors are not actually designed to hold a particular position in a "stalled"
condition.   Some are,  but most are not.

Thats why you can buy a servo to accomplish the same thing.

JimboZA

#9
Jan 24, 2013, 05:58 am Last Edit: Jan 24, 2013, 06:07 am by JimboZA Reason: 1

Thats why you can buy a servo to accomplish the same thing.


Seems to me that this is a project to basically build a servo from first principles....
Roy from ITCrowd: Have you tried turning it off an on again?
I'm on LinkedIn: http://www.linkedin.com/in/jimbrownza

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