Help, motor!!!

[microzone]

I just unscrew my old printer. Inside my printer there has a 12V bipolar stepper motor. I have search through the internet and find it hard to find a driver to drive my 12V bipolar stepper motor. Actually I need a driver to control my motor speed and direction. A motor direction can be control by voltage (Example: 5V is clockwise or 0V is counterclockwise) because I need to use my PIC, microcontroller to control its direction. Can anyone help me? Thank you first for your kind help.

 

[dknguyen]

Can you buy a stepper control? They can be tricky to build. If you must build it (I have never done it or even worked with stepper motors), but the basics of it is you need to use (at a minimum) one power MOSFET per winding on the stepper motor, so that your MCU can control the larger motor current flowing through each winding. You also want some large capacitors to smooth out the voltage spikes. YOu then must use your PIC to switch the MOSFETS in a sequence to energize the windings of the stepper motor in a sequence to get it to rotate (or lock) the way you want it to.

You then have a driver for every winding in the stepper motor and your PIC must use the driver to energize the windings in a sequence in order to get the motor to rotate. This is where I dont quite understand what you mean when you say 5V is clockwise or 0V is counterclockwise...but I dont have the motor in front of me to see how it is built.

I hope this helps.

 

[bryan1]

Hiya Microzone,
Since you pulled the stepper motor from an old printer take a look on the circuit board and their will be a stepper driver chip onboard. I've pulled apart quite a few printers just for the steppers and driver chips and stuff so when a new idea or project comes along I have 99% of the gear already without breaking the bank buying stuff. Also goggle bipolar motor circuits and learn about H-bridges and driving them. There are a heap of chips avaliable for driving steppers both biploar and unipolar but for small steppers a simple h-bridge usually works fine for bipolar motors.

Hope this Helps

Cheers Bryan

 

[dknguyen]

You can use an h-bridge on a stepper motor? Or is only on a bipolar motor?Am I missing something? I thought the windings had no polarity and were always only on or off?

 

[Nigel Goodwin]

You can use an h-bridge on a stepper motor? Or is only on a bipolar motor?Am I missing something? I thought the windings had no polarity and were always only on or off?

You only need an h-bridge for bipolar, the more comon unipolar motors simply require four driver transistors.

As you're using a PIC, the PIC can do all the stepping required, it's a trivial (and common) application - just requires four output pins to feed the drivers.

 

[microzone]

Thanks for your kind reply. Actually I have spoilt my 12V bipolar stepper motor driver when take out my motor. In fact, I also plan to buy one control circuit but I cannot learn how to build a bipolar stepper motor driver. Can you please show me the circuit diagram so that I can build myself and in the same time I also can learn the theory. Thanks

 

[Nigel Goodwin]

Thanks for your kind reply. Actually I have spoilt my 12V bipolar stepper motor driver when take out my motor. In fact, I also plan to buy one control circuit but I cannot learn how to build a bipolar stepper motor driver. Can you please show me the circuit diagram so that I can build myself and in the same time I also can learn the theory. Thanks

For a bipolar motor you need two H-bridge drivers, if you google for "stepper motor tutorial" you will find plenty of information and examples.

 

[bryan1]

Hiya Microzone,
Nigel has given you some very good advise above I've played around with the sn755410 H-bridge driver from TI which is rated at 1 amp and only one chip is needed for a bipolar motor. One thing I found the chip got pretty hot quickly so I stacked another chip ontop and made up a heatsink to sit ontop of the chips and it drove my 5 volt 1 amp biploar stepper on my cnc machine I'm making without cutting out due to heat. That chip is used a fair bit in robotics so you can find a heap of info by searching and this chip will cut down on the parts count.

Cheers Bryan

 

[elcopart]

Here the schematic for bipolar stepp motor driver.

 

[microzone]

Here the schematic for bipolar stepp motor driver.

Thanks elcopart for your bipolar stepper motor driver, can you please send the bipolar stepper motor driver to me it is because I cannot download it? My email address is microzone98@hotmail.com. Thanks.

 

[kamdy]

Hi
you can use the L297and L298 to control and drive your stepper motor you can get the data sheets from ST microelectronics. The web address is
www.st.com/stonline/books/pdf/docs/1734.pdf
www.st.com/stonline/products/literature/ds/1773.pdf

 

[philba]

A motor like that (12V printer stepper) probably doesn't draw that much current. I have successfully driven printer steppers with an L293D and a small pic (you need 2 inputs and 5 outputs at the worst case). Here is the bare-bones schematic. parts cost new is about $6 though you can use a cheaper pic than the F88 that I used as long as it has 7 I/O pins available.

You can cut the pin count by 2 pins if you invert the A1 and B1 outputs (via transistors) to get A2 and B2 but you can't do half stepping then. then you could use an 8 pin PIC.

 

[microzone]

A motor like that (12V printer stepper) probably doesn't draw that much current. I have successfully driven printer steppers with an L293D and a small pic (you need 2 inputs and 5 outputs at the worst case). Here is the bare-bones schematic. parts cost new is about $6 though you can use a cheaper pic than the F88 that I used as long as it has 7 I/O pins available.

You can cut the pin count by 2 pins if you invert the A1 and B1 outputs (via transistors) to get A2 and B2 but you can't do half stepping then. then you could use an 8 pin PIC.

Thanks, philba. Can you give more info to me about this because I am a newbies and not so understand about the schmeatic that you have provide? May I know is what is P2 in your circuit diagram, is it another IC or L293D? Thanks Philba.