Stepper motor controller needed

[LegoHead]

I have been looking for hours! Checked RS and maplins

I will even be happy for the circuit to build my own controller.

Anybody got a circuit diagram for stepper motor controller in full step mode?

Its for a four phase unipolar stepper motor.

cheers,

David.

 

[sn00p]

I have been looking for hours! Checked RS and maplins

I will even be happy for the circuit to build my own controller.

Anybody got a circuit diagram for stepper motor controller in full step mode?

Its for a four phase unipolar stepper motor.

cheers,

David.

You'll be needing 2 h-bridges, one for each coil - just look up the h bridge circuit, it's 4 transistors arranged in a H so you can alter the direction of the current flow. You'll also need a few logic gates to control the gates of the transistors so that you can accept a single "step" input.....

Alternatively, there's a chip that costs like £1 or so (in quantity - we've just used one in a project at work) but I can't remember the chip number, we've got it at work, but I'm not at work.....If I remember on monday I'll post here again.

Bipolar steppers are much easier to drive as they have a centre tap on the coil so you don't need the h bridges.

 

[LegoHead]

Thanks, already got the L297 i think it is from RS that will drive the coils, I am just looking a circuit to generate the correct sequence now, i have one but it's not reliable.