I'm using 1Hz clock pulse using 555 timer and 4017 counter is used to drive ic L293D. 4017 counter works correctly but motor driver ic L293D does not show any voltage (also 0.85 Volt) to drive stepper motor.


I used this configuration. I can't find where is the problem in my circuit diagram. Please help me......

 

use this circuit: http://library.solarbotics.net/circuits/driver_stepper_nu.html
i know it works because iv used it..
instead of driving the motor directly from the EXOR.. run the signals into the L293D to boost the current/voltage.

see the site for explanation

<edit>
Sorry, Above is wrong, it doesnt have a step signal..
this is the one i mean

 

I have another question about rotating a stepping motor, as I'm about to buy one.

Is it do-able to make it move only one or two steps and then come to a standstill? Or is such small amount of steps not possible due to issues with high inertia torque / starting torque / overshooting or so?
Does this give problems or is this within the normal range of applications of stepping motors?

 

You can step a stepper step by step (as weird as it looks written) and make it stop and hold any given time, that's the magic of steppers..

 

My problem is solved. Thanks to all.

 

Now i want to make variable clock pulse 1Hz to 100Hz.

 

stepper motors are great..
@pavelnedved: in essence, when you turn a stepper motor you are turning it, step by step.. so turning it just once is what it does!
@Felo, that does look weird written "stepper step by step" but they are magical creations.
@Shyamal805... please tell us what you did to fix the problem.. its always interesting to know what went wrong and how you fixed it.

 

You can even step a stepper motor much less than a step. It's called microstepping and it's done by using s sine-wave. You can rotate the stepper almost as small an angle as you want simply by using two 90 degree out-of-phase sine waves first at at standstill, then advancing the sine waves by a small fraction of a full cycle. The only limitation is not to advance the amount too fast or at too high a load or it may not advance as expected. But this is easily controlled by the frequency of the sine wave. Move a few degrees a stop/hold. This can make a stepper run smoothly like a servo motor. And the sine wave currents needed can be made by PWM methods that are very efficient.

This is nothing new and is often used in printers and other applications.

Regards,
Kamran Kazem, V.P., CTO
Magnetic Design Labs, Inc.