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Subject: 
Re: calculating sensor resistance (Ohm's Law)
Newsgroups: 
lugnet.robotics
Date: 
Sun, 8 Apr 2001 14:08:16 GMT
Original-From: 
Pete Sevcik <psevcik@austin.rr.STOPSPAMMERScom>
Viewed: 
959 times
  
Michael,
As usual, you are correct.  Thanks for pointing out my error.
    - pete.

Michael Gasperi wrote:

Pete Sevcik <lego-robotics@crynwr.com> wrote in message
news:3ACE6E90.3FA776D0@austin.rr.com...
Lauren,

Your diagrahm is correct.  Your voltage assumption is not.  On RCX the • full
scale is 2 volts to 5 volts, not 0-5 like you have assumed.  Try
re-calculating with a 3 volt span.

That is not true for passive mode.  The scale is 0v = 0 and 5v = 1023 in
passive modes like touch or temperature.

The problem with what Lauren is doing is that the Temperature conversion is
far from linear.  There is a piece-wise conversion inside the RCX used to
fit the thermistor's curve.  You really need to use the raw digital values.
There are ways to see the raw value using standard RCX code, but not ways to
use the values in a RCX code program.  If you need some more background see:
http://www.plazaearth.com/usr/gasperi/lego.htm

--
Pete Sevcik     sevcik@flash.net
Techno-stuff Robotics
http://www.flash.net/~sevcik/
Robotics for FUN !



Message is in Reply To:
  Re: calculating sensor resistance (Ohm's Law)
 
Pete Sevcik <lego-robotics@crynwr.com> wrote in message news:3ACE6E90.3FA776....rr.com... (...) full (...) That is not true for passive mode. The scale is 0v = 0 and 5v = 1023 in passive modes like touch or temperature. The problem with what Lauren (...) (24 years ago, 7-Apr-01, to lugnet.robotics)

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