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 01:28:40 GMT
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Original-From:
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MAR ERICSON <mar@cooper/spamless/.edu>
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Viewed:
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1336 times
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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 Advancement of Science and Art
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On Mon, 10 Nov 1997, marco antonio assfalk oliveira wrote:
>
>
>
>
>
> 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 2 Replies:
 | | Re: Burning hot motor driver chips.
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| Anthony can correct me if I'm wrong, but generally the phrase "converting an R/C car" means, taking a Radio Controlled model car, modifying and/or removing the radio receiver and motor driver circuitry, and replacing it with a computer. The generic (...) (27 years ago, 1-Oct-97, to lugnet.robotics.handyboard)
| | | Re: Burning hot motor driver chips.
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| (...) Well, that's partially correct. The RC cars usually have a speed control/ steering module that incorporates the RF receiver. This module supplies PWM signals to the drive motor and also controls a steering servomotor. Marco A.A. de Oliveira (...) (27 years ago, 11-Nov-97, to lugnet.robotics.handyboard)
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