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Topic: Hooking up a 3.15v stepper motor, posible? (Read 956 times) previous topic - next topic

madworm

#5
Aug 27, 2008, 03:43 pm Last Edit: Aug 27, 2008, 03:45 pm by madworm Reason: 1
This driver seems perfect. I'd buy it :-)

If you read the data sheet you'll find information about current sensing/limiting. You'll need exactly 2 current sensing resistors and a reference voltage to set the maximum current the driver will pass to your bipolar stepper motor. The rest is done internally. Protective diodes and so forth are already built into the driver's H-bridge circuitry. As mentioned before you'll need a higher supply voltage than the voltage rating on your stepper motor to give the driver a chance to counteract the stepper's high inductance, that is make the phase current rise quickly enough to get a decent torque at higher rpm.

The data sheet is on the page you've posted.

http://greta.dhs.org/EasyDriver/


Edit: all of this stuff is already on the PCB sparkfun sells.
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drone

I'll second the vote on the easydriver - I'm currently using 3 on my project.

As madworm pointed out, you really don't need any special voltage regulation, the driver chip will do it for you.

For example, I run two arduinos and three stepper motors (rated @ 6v/0.8A each) off one 12v/3A power supply.  I used the easydriver's current adjustment to tune down the motors to the exact amount of current necessary (well below the actual 800mA, which the easydriver cannot provide -- it's limited to 750mA, IIRC) to drive the load that each needs.

Be warned, the chips on the easydrivers can get quite hot, make sure to account for any ventilation needs.

!c

ndeboar

Fan-tiddly-tastic.

I am just really getting started on Ardunio, so this sort of "basic" help is a life saver.

Cheers, will post my little project when im done!

Nick Deboar
www.nickdeboar.com

drone

#8
Aug 27, 2008, 07:47 pm Last Edit: Aug 27, 2008, 07:48 pm by drone Reason: 1
It's really easy to use, just hook up the A and B coils to the appropriately labeled inputs on the easydriver, the Vin and GND to the appropriate inputs, then one digital pin from the arduino to each of the STP (step) and DIR (direction) inputs.

Then, you just change the direction by digitalWrite()'ing HIGH or LOW to the DIR pin.

To make it perform one step, just write HIGH to the STP pin for about 3ms, and then bring it low.  It'll only make one step for each transition from low to high.

!c

absolutum

EasyDriver is really a neat solution

and if you ramp the stepper at start and stop you will get it really smooth

I use two oft them to dirve my robotic panorama head

cheers
Paul

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