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Subject: 
Re: Robolab, byte codes and assembler
Newsgroups: 
lugnet.robotics, lugnet.robotics.rcx.robolab
Date: 
Sun, 30 Nov 2003 17:20:53 GMT
Viewed: 
3945 times
  
In lugnet.robotics, Mark Tarrabain wrote:
Could someone explain to me technically why this sort of of problem with
the rotation sensor occurs?

I know how quadrature shaft encoders are _supposed_ to work, and I can't
see why this sort of thing should happen in the first place.

Mark

The way I understand it, it's really not the sensor's fault.  The RCX and
firmware together either can't or doesn't deal with the ambiguous voltage levels
sometimes returned during two of the four transitions.  If the RCX were fast
enough that the firmware could keep sampling until the state was no longer
ambiguous without the risk of missing a quadrant entirely, the problem would go
away.

The _low speed_ problem, on the other hand, _is_ the sensor's fault.  At a
specific point during the trasition, the voltage starts oscillating.  Some sort
of "debouncing" is needed, like an added filter capacitor.



Message is in Reply To:
  Re: Robolab, byte codes and assembler
 
Could someone explain to me technically why this sort of of problem with the rotation sensor occurs? I know how quadrature shaft encoders are _supposed_ to work, and I can't see why this sort of thing should happen in the first place. >> Mark (21 years ago, 30-Nov-03, to lugnet.robotics, lugnet.robotics.rcx.robolab)

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