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Sunday, May 22, 2011

Notes on the heavy duty motor shield for Arduino


This is a heavy duty motor shield for Arduino

It uses the basic motor shield from adafruit.com, same software, but instead of an hbridge
driver, it uses 25A 60V mosfets for drive.  Purpose is to drive
drill motors from the Arduino.

Here is the circuit of a half bridge.  The extra devices on the left are
to convert the input & enable structure to a N and P drive.  It is important
to have a HiZ mode when disabled, where N=0 and P=1 and both
MOSFETs are off.  I hope to simplify this circuit but i don't want to make
major modifications to the adafruit.com library.  This is the lash up prototype:



Here is  a photo of the Arduino, a canabalized up motor shield on top (this was one i modified for stacking and later blew out an Hbridge IC on, doh!) for control, a breadboard full of the NPN and PNP needed to convert the interface, a prototype high current MOSFET driver board and a drill motor.  The motor power supply is not connected in this photo.

Lets see if I can post the little video of the motor test program.  It revs the motor speed up, then reverses, then stops and repeats.  Watch the little black gear and make sure your sound is on to hear the fun.


video

Now to clean up the board to the form factor of a shield, it will be somewhat dense.


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