Position control of a DC motor - arduino

Its back, new and improved! Using a printer I got at a garage sale this weekend, I made another servo out of a DC motor. I used the optical encoder from the printer and interrupts on the arduino for feedback of the position. A pot controls the position. A SN754410 drives the motor. I got help with the encoder/interrupt code from this website http://abigmagnet.blogspot.com/ from his post doing basically the same thing I just did. This thing isn't effect by the PID constants as much as the other servo I made.

I was planning on doing the same thing with the print head but accessing the encoder pins on that board is a little tricky.

Now I just have to make something useful out of it.

Category:

Science & Technology

Tags:

• arduino
• pic
• pid
• microcontroller
• c/c++
• basic
• programming
• motor
• servo
• dc
• ac
• electronics
• batteries
• bridge
• optical
• encoder
• pot
• position
• control

[rhonmanalo]

what do you call that circle transparent plastic?

[Andrewinadoghat]

@rhonmanalo I would call it an encoder code wheel.

[rodstartube]

@momavalencia lol. Position is controlled by comparing the real position (sensor's feedback) versus desired position. In this case, sensor feedback is a quadrature encoder (the transparent plastic wheel), and the control is the potentiometer (or joystick) in the guy's hand. Who does all this? a microcontroller with running software on it. Yes you can also attach a pot to mechanism, acting as sensor (feedback). In fact RC servos work like that while desired input is PWM. Pro servos are brushless.

[jard18]

If you want more precision, you would put the encoder directly on the motor shaft.

[momavalencia]

Sir how do you control the position of the motor? How do you check the position error? Connecting a potentiometer to the shaft of the dc motor?

[momavalencia]

Sir how do you control the position of the motor? How do you check the position error? Connecting a potentiometer to the shaft of the dc motor?

[srmack68]

I am looking to do something very similar with a dc motor with an encoder attached. Can you please share the code with me so I can get started. I will be controlling it with a pot as you did also. I ant find any code in the link you posted. I would appreciate any help at all.