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In lugnet.technic, Mark Tarrabain wrote:
> Kevin L. Clague wrote:
> > You are doing well Mark. You can use three voltage comparators to detect which
> > voltage level is being output. What you need is three comparators. One for
> > 25%, then 50%, and 75%. If 75% is on, then you'll need to gate off the 25% and
> > 50% outputs. If 50% is on, you'll need to gate off the 25% output. If 25% is
> > not on, then you know you have no power, giving you four levels.
>
> I was thinking that one could just use an ADC to directly convert the
> analog voltage level to a digital number of however many bits you could
> resolve it to and then taking that binary number to address a demux and
> have the demux's outputs drive the switches.
>
> Using a single ADC instead of a comparator for each voltage level would
> use far fewer chips, for anything above 4 voltage levels, at the very
> least. I'd bet that it's probably completely feasable to individually
> drive 16 or maybe even 32 switches from a single RCX port this way.
When using LEGO's firmware and NQC the maximum number of power levels you have
is 8 (plus off?), so the most you can identiy is 9. This of course presumes
that current draw by your compressor's motors doesn't mess with the voltage
going into your ADC, or the ADC's ability to give consistant readings.
With BrickOS, you have better resolution for power control, so maybe you could
address more, but again, the question is what kind of inaccuracies are
introduced by driving the compressor (or other motors).
What happens to the solenoids that are not being addressed? I've not messed
with solenoids since my youth (a long, long time ago :^), but I thought that
they had springs to make them go one way, and electromagnets to make them go the
other. Remove the power from the electromagnet and the spring returns solenoid
to its original state.... Do your electronics need to remember state?
>
> > > Mark
Kevin
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Message has 1 Reply:
 | | Re: EGAD! (pneumatics)
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| (...) Yes, the switches would need to remember their last set state. Ideally, this would be done through the use of electric pneumatic switches which, when not receiving any power, simply stay in the last position they were set in. If this isn't (...) (21 years ago, 16-Jun-03, to lugnet.technic, lugnet.robotics)
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Message is in Reply To:
| | Re: EGAD! (pneumatics)
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| (...) I was thinking that one could just use an ADC to directly convert the analog voltage level to a digital number of however many bits you could resolve it to and then taking that binary number to address a demux and have the demux's outputs (...) (21 years ago, 16-Jun-03, to lugnet.technic, lugnet.robotics)
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