1. PROMGRAMING YOUR ROBOT
Controlling Distance
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2. Loops Infinite loops Finite loops Doesn’t know when to stop
Can’t get out of the loop
Finite loops
Defined start and stop time
For… next commands to specify the number of times to execute the loop
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3. Example Code ‘ ------Declarations -----
pulse_count var word ‘Declare a variable for counting
LOW 12 ‘reset ports
LOW 13
' ---- Main routine -----
main:
forward: ' Forward routine
FOR pulse_count = 1 TO 100 ' Loop that sends 100 forward-move pulses
PULSOUT 12, 500 '1.0 ms pulse to right servo
PULSOUT 13, 1000 '2.0 ms pulse to left servo
PAUSE 20 pause for 20 millisecond (20 ms)
NEXT
STOP ‘stop until the reset button is pressed
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4. Variable Declaration
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5. Now Your Turn Make the robot go backwards and then stop
Make the robot go forward, pause, and then backwards, and stop
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6. Distance Calculation Circumference of the Boe-Bot wheel:
π* wheel diameter = * 6.67 cm » 21 cm.
We need 21cm for one complete turn
At full speed, the servos turn at 37.5rpm or rev/sec
21 cm/revolution * revolutions/sec = cm/s.
The time it takes to make the Boe-Bot travel 50 cm is ;
ttravel = 50 cm/ cm/s » 3.81 seconds
Since the pulse and pause periods are known, the time it takes for a single loop can be calculated:
tloop = 1.0 ms ms + 20 ms = 23 ms
Left and right wheels
Pause
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