Motor shield half bridge

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eliasm307
 
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Motor shield half bridge

Post by eliasm307 »

I just want to make sure. The motor shield in the link below supports up to 4 bi-directional motors, so it also means it supports 8 uni directional motors in half bridge mode, right. And what would the code for controlling these motors look like

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adafruit_support_bill
 
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Re: Motor shield half bridge

Post by adafruit_support_bill »

The raw L293D chips could be used that way. But as the shield is designed, a single PWM signal is use for speed control on each pair of half-bridges. So both motors would have to be going the same speed.

eliasm307
 
Posts: 9
Joined: Sun Nov 18, 2012 11:48 am

Re: Motor shield half bridge

Post by eliasm307 »

What if I put a motor.setSpeed() command in between the commands used to control the two motors. For example:

motor.setSpeed(100);
motor.run(FORWARD);
motor.setSpeed(200);
motor.run(BACKWARD);
delay(
...blah blah blah

Would this not run the half bridge motors at different speeds

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adafruit_support_bill
 
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Re: Motor shield half bridge

Post by adafruit_support_bill »

No. There is only one pin that controls the PWM signal to both halves of the bridge.

eliasm307
 
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Re: Motor shield half bridge

Post by eliasm307 »

Ok thanks. I also have another question, I know it can handle 4.5V to 25V for powering the motors but what about the current, are there limits to what current it can withstand.

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adafruit_support_bill
 
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Re: Motor shield half bridge

Post by adafruit_support_bill »

The basic shield will handle up to 600mA (0.6A) on each motor channel. See the FAQ for details on how to modify it to handle higher current loads: http://forums.adafruit.com/viewtopic.php?f=31&t=26873

eliasm307
 
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Re: Motor shield half bridge

Post by eliasm307 »

Ok, thank you very much

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