Subject:
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Re: sensor input mux calculations
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Newsgroups:
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lugnet.robotics
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Date:
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Tue, 29 Dec 1998 19:44:36 GMT
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Original-From:
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Fred Bauer <fred.bauer@wcom.comIHATESPAM>
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Viewed:
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1328 times
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I've been looking at the multiple sensor input problem... wouldn't it be
simpler to use a series resistor network, rather than parallel, something like
this:
--|--[ 10 ohm ]--|--[ 20 ohm ]--|--[ 40 ohm ]--|--[ 80 ohm ]--|--
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-------X---------------X--------------X-------------X--------
where X is a switch.
If the calculations are correct, this should give raw readings between 0 and 31,
depending on which switches are OPEN. This would then be easy to decode.... I
havn't played with this on the RCX, the resistor values may have to be adjusted
or scaled, depending on the accuracy of the A/D conversion, but keeping the
values low makes this a (relatively) linear function.
Fred Bauer
fred.bauer@wcom.com
--
Did you check the web site first?: http://www.crynwr.com/lego-robotics
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Message has 2 Replies:
 | | Re: sensor input mux calculations
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| (...) Thanks, I didn't think of that. Since it is a linear function to convert the measured resistance to the switch values, this is much faster and also has better spacing between the values. Using 300, 600, 1.2k, 2.4k, and 4.8k ohm resistors, you (...) (26 years ago, 29-Dec-98, to lugnet.robotics)
| | | RE: sensor input mux calculations
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| This design would prevent multiple switch detection. Only one switch would be detectable (the last one). The designs people have been creating so far have been capable of detecting 3-4 discrete inputs at any time regardless of the settings of any (...) (26 years ago, 30-Dec-98, to lugnet.robotics)
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