Author Topic: car window motor project  (Read 2862 times)

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Offline rsimpTopic starter

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car window motor project
« on: May 31, 2013, 07:30:10 PM »
I am new to this...and I have a odd project.  I plan on having a 12 volt source (a brake light feed) that activates a window motor to lift a heavy object and lower that object back down once the power is removed from brake light.  There is going to be ~90 degrees of travel which I plan on controlling with limit switches.   The problem that I am having is wiring the darn thing to go back down. 
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Offline jkerns

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Re: car window motor project
« Reply #1 on: June 01, 2013, 07:53:01 AM »
What I originally wrote was not quite right. But, yes you do want to use an H bridge. Either one to control both motors or two bridges - one for each.  The inputs to the bridge to control enable, forward / reverse will be the combination of brake on / off and limit switches.

What is your brake actuated sign going to say to the driver behind you?
« Last Edit: June 03, 2013, 01:14:23 PM by jkerns »
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Offline rsimpTopic starter

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Re: car window motor project
« Reply #2 on: June 01, 2013, 06:23:30 PM »
It is not a sign... it is an active-aerodynamic wing.  Each of the two motors, one for each side, had a 16amp fuse and were on their own circuit. Do you have a suggestion for the type of H bridge for this application?
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Offline jwatte

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Re: car window motor project
« Reply #3 on: June 01, 2013, 10:31:39 PM »
You'd need a 20A or higher rated H-bridge. You *can* build these on your own, using H-bridge drivers chips and power MOSFETs, but that typically requires a lot of trial, error, blown parts, and frustration. Buy something that works.

One of these per motor would probably be robust enough: http://www.pololu.com/catalog/product/759
Make sure to secure the VMot input against load dumps from the starter with a 16V 5000W TVS diode.

If you don't need solid state, two SPDT relays per motor could work, too.
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