The color or light meters do not have a long range. It is optimally read at two pennies height, so yes, you will have to be right on top of the medicine bottles to read them accurately.  Using an ultrasonic sensor in combination with the color sensor would be the obvious fix.
  Set it so that when the ultra sonic sensors senses something within an inch, it moves toward it (to about 3 mm distance) and then reads the color.  This is further complicated by the fact each bottle has a white belly.  (I would set white to make it move forward 1 cm and read again.) You will will either have to master your datawries or do some serious nesting.
  Because the lego color sensor is not very sensitive from a distance, my team choose not to do this challenge. But I'm looking forward to seeing how other teams went about it!

 From: Jill Hamilton <[log in to unmask]>
To: [log in to unmask] 
Sent: Tuesday, October 23, 2012 10:12 PM
Subject: [VADCFLL-L] Sensitive Light Sensor

Light sensor difficulties:  Our team would like to use the light sensor for the medicine bottle mission.  But the sensor seems to only read accurately if you are practically touching the line or bottle it is trying to read (meaning no room for error). This makes it difficult to do this mission with consistency.  Is there a way to allow it read at a greater distance from the line or object?  I can’t find much guidance on the web.  Thoughts? 
Jill Hamilton
Electric Pineapples

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