Subject:
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Re: multi-device output controller
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 26 Mar 1999 17:34:25 GMT
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Viewed:
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947 times
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alex wetmore wrote:
> On Fri, 26 Mar 1999, Lou Sortman wrote:
> > Joel Shafer wrote:
> >
> > > What about a real time circuit that routed the output power to one of eight
> > > output ports depending on the PWM. That way it only takes one output port
> > > on the RCX and up to three (out of 24) motors could be running at the same
> > > time.
> >
> > And where are you getting motor drive power from? I assume you want the selected
> > motor to run at full power, not at 1/8, 1/4, etc. I'm afraid you're still stuck
> > consuming the extra output for power unless you use a separate power source.
>
> With a seperate battery box (from 8735 for instance) you could power the
> output full time. In this case you'd probably want to map it to something
> like this:
> off - off
> 1 - output 1 fwd
> 2 - output 1 rev
> 3 - output 2 fwd
> 4 - output 2 rev
> 5 - output 3 fwd
> 6 - output 3 rev
> full - output 4 fwd
>
> (if there is a 7 then you could get 4 outputs in fwd and reverse).
> You would get a max of 9 (or 12) outputs, but I think that would
> be plenty for most RCX-type robots (I still really haven't had to
> go beyond 3 outputs, but I've mostly built vehicles).
>
> alex
There are 8 levels of PWM, so fwd/rev for 4 devices is possible. I originally wanted a
separate power input to allow a full 8 levels for each device. This would allow the
controller to operate ANY device designed for the RCX ports and not assume a motor is
connected. I am also toying with the idea of using the PWM to operate a stepper
motor. Having a range of PWM would be very useful in that case.
Now that I have brought up that topic, anyone know how to drive a stepper motor w/ RCX
PWM?
-Wes
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Message has 1 Reply:
 | | Re: multi-device output controller
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| (...) Are you sure? I wasn't, so I went looking. The NQC docs seem to imply 7 powers levels plus off. Which, technically, is 8 levels of PWM, but if you use all of them, a motor is running at all times. That is fine if you use another motor output (...) (25 years ago, 26-Mar-99, to lugnet.robotics)
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Message is in Reply To:
| | Re: multi-device output controller
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| (...) With a seperate battery box (from 8735 for instance) you could power the output full time. In this case you'd probably want to map it to something like this: off - off 1 - output 1 fwd 2 - output 1 rev 3 - output 2 fwd 4 - output 2 rev 5 - (...) (25 years ago, 26-Mar-99, to lugnet.robotics)
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