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Subject: 
Re: color sensor: was ( Light sensor values)
Newsgroups: 
lugnet.robotics
Date: 
Sat, 18 Sep 1999 09:56:00 GMT
Original-From: 
Stephen P. Gibbons <{steve@aztech.net}nospam{}>
Viewed: 
1873 times
  
Pure-Lego (but more than one input/output unless a motor can be driven off of the
output to a light sensor and the input from a light sensor and rotation sensor can
be multiplexed):
1) 1 light sensor
2) 1 (micro)motor to drive the rotation of the filtering lenses
3) 1 rotation sensor/fibre-optic to detect which lense is in place at a given
moment

Games will probably need to be played with the gearing, in order to get the
filters and rotation sensors in synch.

I can think of two sets of filters that would probably be useful:
RGB: (one red, one green, one blue, at 120o each.)
CMYK: (one blue, one red, one yellow, and one clear at 90o each)
I think the second is probably more achievable using Lego blocks than the first,
and gives the advantage of obtaining unfiltered readings from the light sensor.

Joel Shafer wrote:

> At 11:17 PM 9/17/99 +0000, you wrote:
> > On a (somewhat) related note: How would it be possible to use three light
> > sensor, with some sort of colored filter setup to differentiate color?  Most
> > importantly is there any way to combine thier input into one sensor port?  I
> > can image some ways using two ports, but if there was some way to use the raw
> > value to tell predominant color (say 0 - 300 for red, 400-700 for blue,
> > etc..)
> > from one port, that would be interesting.
> 
> It seems like you could get about 3-4 bits for each color if you were only
> using one input port.  That's not very good resolution.  Perhaps a better
> way would be to design a color sensor and use a pic chip for it's
> brain.  It could sample all three sensors, save the results then send the
> them to the port one color at a time.  It could alternate the top bit so
> that the software could determine which color reading was coming
> in.  Pretty far fetched I'm sure...
> 
> Joel Shafer    joel@connect.net


--
S

"Paranoia strikes deep\ Into your heart it will creep\ It starts when
you're always afraid\ (Step outta line, the man come and take you away)"



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Message has 2 Replies:
  Re: color sensor: was ( Light sensor values)
 
More simlple : use the sensor input mux by Michael Gasperi. You can easily connect 3 (up to 7) passive sensors to one RCX input. I've completed mine, but didn't test it already. "Stephen P. Gibbons" a écrit : (...) ---...--- Philippe Jadin (...) (27 years ago, 18-Sep-99, to lugnet.robotics)
  Re: color sensor: was ( Light sensor values)
 
Stephen P. Gibbons <lego-robotics@crynwr.com> wrote in message news:37E361B0.6CA5FE...ech.net... (...) of the (...) sensor can (...) given (...) You have a good idea, but the LEGO light sensor is a silicon photo transistor which is mostly sensitive (...) (27 years ago, 18-Sep-99, to lugnet.robotics)

Message is in Reply To:
  color sensor: was ( Light sensor values)
 
(...) It seems like you could get about 3-4 bits for each color if you were only using one input port. That's not very good resolution. Perhaps a better way would be to design a color sensor and use a pic chip for it's brain. It could sample all (...) (27 years ago, 18-Sep-99, to lugnet.robotics)

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