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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.NETnospam>
Viewed: 
627 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 (...) (25 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 (...) (25 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 (...) (25 years ago, 18-Sep-99, to lugnet.robotics)

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