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Controlling a motor through PWM (Read 5101 times)
03/21/07 at 03:15:42

janes   Offline
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I am trying to control a motor that requires a pulse from 1 to 2 ms that is generated every 20ms. I thought that maybe the 8 PWM could be used to drive 8 of these motors. Does anyone know how to accomplish this using them?

Thanks in advance
 
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Reply #1 - 03/21/07 at 04:36:26

barragan   Offline
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This example shows how to drive a motor using pwm and an L293D motor driver chip: http://wiring.org.co/learning/examples/driving_dcmotor.html
You could use all the 6 PWM outputs to drive motors, each L293D can handle 2 motors.
 
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Reply #2 - 03/22/07 at 00:50:05

janes   Offline
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I tried looking for the L293D on the internet but couldn't really find any specs for it but it doesn't appear to be what I am trying to do. I need to actually control a PWM motor or servo that requires a pulse of 1 to 2 ms every 20ms. One example is the Futabo continous servo at http://www.parallax.com/dl/docs/prod/motors/crservo.pdf.

Is this even possible with the 6 onboard PWM?
 
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Reply #3 - 03/22/07 at 04:57:46

barragan   Offline
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It is probably one of the most used chips to drive motors and stepper motors, here is the datasheet http://focus.ti.com/docs/prod/folders/print/l293d.html
google L293D and you'll get lots of documentation and selling places.
You can control any generic servo, Hi-Tech, Futaba etc using the Wiring Servo library http://wiring.org.co/reference/libraries/Servo/index.html, you can hook up to 8 servos directly to the wiring board in any pin (not just the PWM output pins) here there is an example as well http://wiring.org.co/learning/examples/driving_two_servos.html
If your application requires to handle lots of servos there is also an example using the PicoPic servo board http://wiring.org.co/learning/examples/picopic_serial.html
each board can control up to 20 servos.
It always possible to hack a regular hi-tech servo and make it continuous, actually it is quite easy, check this http://www.seattlerobotics.org/guide/servohack.html this one is also good http://www.tedpavlic.com/post_servo.php
 
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