Subject:
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Re: FindLight
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Newsgroups:
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lugnet.robotics
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Date:
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Mon, 26 Feb 2007 06:34:52 GMT
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Viewed:
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3729 times
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In lugnet.robotics, linmix <linmix@gmail.com> wrote:
> I've declared turnfind at the beginning and set it to 0 (just in case)
> According to BricxCC's 'Watching the brick' the values are ok, but no
> matter what the values the robot will only spin back for a fraction of a
> second.
//findlight.nqc
#define A OUT_A
#define C OUT_C
int maxlight;
int light;
int time = 0;
#define TURNTIME 500; //change to accomodate 1 turn
#define ROTATE_CLOCKWISE OnFwd(A); OnRev(C);
#define ROTATE_COUNTERCLOCKWISE OnFwd(C); OnRev(A);
task main()
{
SetSensor (SENSOR_2, SENSOR_LIGHT);
// measure light level at start of program
maxlight = SENSOR_2;
// turn slowly by lowering the motor power level
SetPower(A+C, 3);
// start rotating
ROTATE_CLOCKWISE;
// reset timer to zero
ClearTimer (0);
// rotate for 5 seconds
while (Timer (0) < TURNTIME)
{
// measure current light sensor reading
// use a variable so the value doesn't get re-read from
// from the sensor inside the if statement
light = SENSOR_2;
if (light > maxlight)
{
// if it exceeds previous max then remember the new reading
// and the time when we found it
maxlight = light; // set maxlight to new max value
time = Timer(0); // remember when maxlight was found
}
}
// after rotating clockwise for 5 seconds now rotate back the other way
ROTATE_COUNTERCLOCKWISE;
// wait until we are back to the time when we found the maximum light
Wait (TURNTIME - time);
// stop turning
Off (A+C);
}
What value do you see for time in the Watch window after your program runs?
Does the value correspond to the number of 1/100s of a second from the start of
the program where the maximum light should have been found?
You are better off using a constant for TURNTIME since it never changes. I
defined macros for clockwise and counter clockwise rotation just to make it
better describe what you are trying to tell the robot to do. You should adjust
the definition of these macros so that they actually match your robot's
configuration.
John Hansen
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Message has 1 Reply:
 | | Re: FindLight
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| (...) I accidentally put a semicolon on the #define line above which is wrong. The program I posted will not compile unless the semicolon is removed. My apologies. It's what I get for posting late at night. John Hansen (18 years ago, 26-Feb-07, to lugnet.robotics)
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Message is in Reply To:
| | Re: FindLight
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| Thanks. I thought setting maxlight before the 'if' statement would be enough, but moving it closer to the front (before the 'while' statement') did the trick. The bit after the while loop still gives me pain though. I've changed it a bit to be able (...) (18 years ago, 25-Feb-07, to lugnet.robotics)
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