You should always calibrate when you move to a different table or have different lighting in the room just to be on the safe side. You have no real idea of what it looks like under your robot, and the slightest change can make a difference.

Darlene Pantaleo
FLL Judge Advisor
Maggie Walker
P/F: 804.745.2493



On Nov 2, 2010, at 12:10 PM, Lloyd O'Hara wrote:

> Ok, I have a question about calibrating light sensors.  Currently we are using light sensors but have them setup to work on our practice table.  The sensors generate light and are using reflected light for the readings.  Additionally, the sensors are inside the the body of the robot and are vey close to the mat. and are pretty much are blocked from ambient light.  So much for what we are doing, it would seem to me, if most ambient light is excluded and the sensor is generating its own light and measuring the reflected light and the sensors are very close to the mat, then we should get the same readings no matter what the venue light is like and we should not need to calibrate. 
>  
> Are we way off base on this one?  We'll calibrate just in case but it doesn't seem like we should have to.  These new sensors are not like the old RCX ones.
>  
> Lloyd
> 
> 
> Nov 2, 2010 10:47:41 AM, [log in to unmask] wrote:
> Kevin,
> 
> One way would be to put on a move block in the direction you want to go followed by a wait block for light sensor. The move block should be set for unlimited rotations and the wait block is set up to look for light < 10 (or some number that will eliminate dark blue, etc).
> 
> Make sure and calibrate your light sensor for the ambient light on your table.
> 
> -Frank
> 
> -----Original Message-----
> From: First Lego League in Virginia and DC [mailto:[log in to unmask]] On Behalf Of Kevin Weaver
> Sent: Tuesday, November 02, 2010 11:33 AM
> To: [log in to unmask]
> Subject: [VADCFLL-L] light sensor and loops
> 
> We had a new idea for one of our missions but are getting stuck on the coding. The kids want to use a loop and let the robot roll until the light sensor sees the black line. We can't figure out how to make it stop moving and go onto the next bit of code at that point. Any tips?
> 
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