Subject:
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How is this?
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Newsgroups:
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lugnet.robotics.nxt
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Date:
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Sat, 23 Jan 2010 19:38:01 GMT
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Viewed:
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19908 times
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One of my students built the chainsaw model from nxtprograms.com.
He wanted to make the blade turn only when it was at a distance less than 9
inches from the table. So he attached an ultrasonic and made one mod to the
program.
The program in NXT-G is simple:
Loop forever
If Touched
{
wait for ultrasonic < 9"
turn MotorA forward unlimited
}
else
{
turn MotorA off
}
If touched and distance > 9, MotorA does not move.
If touched and distance < 9 MotorA turns
-- If untouched and distance is < 9, MotorA stops
-- If untouched and distance is > 9. MotorA keeps on turning!
The last condition is what's bugging us. Why does the motor not stop if
distance is greater than 9"? I have always assumed the switch block would take
the bottom (negative) logic when untouched. As it is now, the motor keeps
spinning until the ultrasonic detects < 9". Obviously, after the motor starts
turning, it ignores the touch sensor.
We're using NXT-G 2.0
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Message has 1 Reply:
 | | Re: How is this?
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| (...) I can see how this can happen and it depends on the sequence of events. This sequence will cause this behavior: touched AND distance < 9 - Motor turns on touched AND distance > 9 - Motor running, waiting for distance < 9 untouched AND distance (...) (14 years ago, 23-Jan-10, to lugnet.robotics.nxt)
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