Subject:
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Re: Burning hot motor driver chips.
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Tue, 11 Nov 1997 01:16:17 GMT
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Original-From:
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marco antonio assfalk oliveira <assfalk@unm.edu*spamcake*>
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Viewed:
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1349 times
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On Mon, 10 Nov 1997, MAR ERICSON wrote:
> What does "RC" stand for anyway? I don't think it's Radio Control...is it?
I believe that's correct: Radio Controlled devices, RC devices.
Marco A.A. de Oliveira assfalk@eece.unm.edu
--------------------------------------------------------------------
Autonom. Robotics (SMART) Project UNM/NASA ACE Center
----------------------- <http://ace.unm.edu> ----------------------
> -----------
> ericson mar
> Master of Engineering Candidate
> Project: Mobile Robotics
> mar@cooper.edu
> (212)353-4356
>
> Department of Mechanical Engineering
> The Cooper Union for the Advancement of Science and Art
> -------------------------------------------------------
>
> On Mon, 10 Nov 1997, Chuck McManis wrote:
>
> > Anthony,
> >
> > As you've no doubt heard, RC motors take much more current than the
> > Handyboard can supply. To control RC motors your only choice is to
> > create a separate H-bridge to drive the motors. You can do this fairly
> > inexpensively with power transistors (TIP125, TIP121) or somewhat more
> > expensively with MOSFETs. I did the latter and have been successful at
> > driving 15 amp motors with the Handyboard. There is a pretty simple
> > circuit on my web page at:
> >
> > http://www.professionals.com/~cmcmanis/robotics/servo.html
> >
> > There are links at the bottom for the MOSFET version that I built up. If
> > I remember I'll put the zip files with the gerber layouts if you want to
> > send them to APC to have some boards made up. The only defect in this
> > design (and the Home brew club here has built up about 40 of these) is
> > that when the battery voltage drops, and the charge pump loses power,
> > the MOSFETs turn off through their linear range and that can cause them
> > to toast if they are in the process of carrying a bunch of current. The
> > solution is to that problem is to add power via a separate battery (the
> > MAX622 takes 20mA peak current) via pin 8. The circuit that works well
> > is a battery tied to pin 8 of the 622 like so:
> >
> >
> > +------------------> To pin 8 of MAX 622
> > |
> > |
> > ---
> > -------
> > --- 9v battery
> > -------
> > |
> > |
> > +------------------> To motor power ground
> >
> > Using the circuit you will probably want a switch on the battery
> > to keep if from draining when the robot is off.
> >
> > A more complete solution is in the works that uses the PR pin of
> > the 622 to cut off power to the FET gates.
> >
> > --Chuck
>
>
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Message has 1 Reply:
 | | Re: Burning hot motor driver chips.
|
| So am I correct to assume that an RC motor had a built in RF reciever? ---...--- ericson mar Master of Engineering Candidate Project: Mobile Robotics mar@cooper.edu (212)353-4356 Department of Mechanical Engineering The Cooper Union for the (...) (27 years ago, 11-Nov-97, to lugnet.robotics.handyboard)
|
Message is in Reply To:
| | Re: Burning hot motor driver chips.
|
| What does "RC" stand for anyway? I don't think it's Radio Control...is it? ---...--- ericson mar Master of Engineering Candidate Project: Mobile Robotics mar@cooper.edu (212)353-4356 Department of Mechanical Engineering The Cooper Union for the (...) (27 years ago, 10-Nov-97, to lugnet.robotics.handyboard)
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