Plenty of great advise on and off the list. It would appear, even though I'm guessing it may not be necessary, we should calibrate the light sensors before each round. To that end I did some investigating on the web so I could find some stuff to teach me and in turn, teach our team of 4th graders at this late stage. What I found is that the NXT help, is not very helpfull in this instance. It's confusing at best. However, after a little looking, I found an easy way to calibrate and also figured out that, as long as we have a good range to detect the black line, we should not have to change anything after calibrating. I was worried about what we would/could do if we figure out at the table that our range is off from the new calibration. Can't change anything at the table, just have to grin and bear it.
Anyway, I found this very understandable NXT program that makes calibration easy. Many thanks to the original author: http://forums.usfirst.org/showthread.php?t=13272&page=2
Thanks,
Lloyd
----- Original Message -----
From: Eric Palmer
To: <[log in to unmask]>
Cc: <[log in to unmask]>
Sent: Tuesday, November 02, 2010 12:53 PM
Subject: Re: [VADCFLL-L] Light sensors and calibration
Lloyd I'm thinking the same as you but just in case.......
Sent from my iPhone
On Nov 2, 2010, at 12:10 PM, Lloyd O'Hara <[log in to unmask]> 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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