about driving a bipolar motor

[jungardc2]

can anyone help me..i got 12 days to make my machine.

the machine involves driving a bipolar motor of a printer.

the problem is i need to drive the motor is such a way that it feeds in and feeds out the paper in the printer.. like the maintenance part of a printer..rolling out of paper.

pls help..

 

[FvM]

What do you mean with bipolar, a DC motor operated in both directions or a bipolar stepper motor?

Bidirectional control of a DC motor is done by a H-bridge, typically with PWM speed control. There are plenty of integrated H-bridge
drivers available with different current capability.

 

[jungardc2]

tnx for the sharing mr FvM..

actually i am a novice here about those kinds of motor..

it is from a printer motor..the one that rolls the paper..
it rotates by step..so it must be a bipolar stepper motor..

the problem is it has 4 leads and when i search some circuits on the internet..
i got circuits for 6 leads..what i mean here is that i got 4 wires from the motor..

the motor got to drive by step when i experiment on this
1 2 3 4 --> leads of the motor
+ - - - --> + is 12v and - is GND
- + - -
- - + -
- - - +



the problem is I got a PIC16F628A to drive the motor..
i tried to have transistor driven relay circuit between the PIC and the motor
but what has come up is not a good way of rotation.
my teacher said that it is because the relay cannot go with the timing.

so now i need a circuit..