photoresistor program

ltmhall

·· I'm designinig a light following robot using a combination of the "flashlight following robot" and
·"avoiding shadows" code from the robotics with the boe bot manual. The code works fine, however,
·when the robot gets within 2 feet of the light it jerks left and right and won't move towards the
·light. I think the problem is that the microprocessor is moving to quick through the code for
·the shawdow avoiding robot code.
·
Any help would be appreciated ?
·

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[noparse][[/noparse] Title ]

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' {$STAMP BS2} ' Stamp directive.' {$PBASIC 2.5} ' PBASIC directive.DEBUG "Program Running!"'

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[noparse][[/noparse] Constants ]

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LeftAmbient CON 132 ' Ambient left lightRightAmbient CON 152 ' Ambient Right lightLeftBright CON 24 ' Bright left lightRightBright CON 43 ' Bright light' Average Scale factorLeftThreshold CON LeftBright + LeftAmbient / 2 * 5 / 8 ' Threshold for leftRightThreshold CON RightBright + RightAmbient / 2 * 5 / 8 ' Threshold for right'

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[noparse][[/noparse] Variables ]

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' left & right photoresistors.timeLeft VAR Word 'Left light measureementtimeRight VAR Word 'Right light measurementmaneuver VAR Nib ' maneuver robotsensors VAR ByteRunStatus DATA 0average VAR Word ' average left and right light valuesdifference VAR Wordtemp VAR WordServoLeft PIN 15 ' Left servoServoRight PIN 14 ' Right servocounter VAR Byte'

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[noparse][[/noparse]Bot maneuvers]

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Forward CON 0 ' ForwardBackward CON 1 ' BackwardRotateLeft CON 2 ' RotateLeftRotateRight CON 3 ' RotateRightPivotLeft CON 4 ' Pivot to the leftPivotRight CON 5 ' Pivot to the rightCurveLeft CON 6 ' Curve to the leftCurveRight CON 7 ' Curve to the right' Servo pulse width rotationsFS_CCW CON 850 ' Full speed counterclockwiseFS_CW CON 650 ' Full speed clockwiseNO_ROT CON 750 ' No rotationLS_CCW CON 770 ' Low speed counterclockwiseLS_CW CON 730'

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[noparse][[/noparse] Initialization ]

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GOSUB Reset ' Uses reset button to start program'

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[noparse][[/noparse] Subroutine - Main Routine ]

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DOGOSUB Test_PhotoresistorsIF (timeLeft < LeftThreshold) AND (timeRight < RightThreshold) THEN 'Is light in view of bothmaneuver=Forward ' move forward if both photoresistors see lightGOSUB Servos_And_SensorsELSEIF (timeLeft < LeftThreshold) THEN ' Left detects flashlight beam,maneuver=RotateLeft ' rotate left if left detects lightGOSUB Servos_And_SensorsELSEIF (timeRight < RightThreshold) THEN ' Right detects flashlight beam,maneuver=RotateRight 'move right if right detects lightGOSUB Servos_And_SensorsELSEGOSUB Look_About ' if light is not found by either photo resistorENDIFPAUSE 20 ' Pause between pulses.LOOP'

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[noparse][[/noparse] Subroutine - Reset]

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Reset:READ RunStatus, temp ' Byte @RunStatus -> temptemp = temp + 1 ' Increment tempWRITE RunStatus, temp ' Store new value for next timeIF (temp.BIT0 = 1) THEN ' Examine temp.BIT0DEBUG CLS, "Press/release Reset", CR, ' 1 -> end, 0 -> keep going"button..."ENDELSEDEBUG CR, "Program running..."ENDIFRETURN'

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[noparse][[/noparse] Subroutine -Servos_And_Sensors]

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Servos_And_Sensors:GOSUB Pulse_Servos ' Call Pulse_Servos subroutine' Call sensor subroutine(s).Pulse_Servos:' Pulse to left servoLOOKUP maneuver, [noparse][[/noparse] FS_CCW, FS_CW, FS_CW, FS_CCW,NO_ROT, FS_CCW, LS_CCW, FS_CCW ], tempPULSOUT ServoLeft, temp' Pulse to right servoLOOKUP maneuver, [noparse][[/noparse] FS_CW, FS_CCW, FS_CW, FS_CCW,FS_CW, NO_ROT, FS_CW, LS_CW ], tempPULSOUT ServoRight, temp' Pause between pulses (remove when using IR object detectors + QTIs).' PAUSE 20RETURN'

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[noparse][[/noparse] Subroutine -Look_About]

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Look_About: ' Starting point labelGOSUB Test_Photoresistors ' Test photo resistors againaverage = timeRight + timeLeft / 2 ' Average both readingsdifference = average / 6 ' take difference' Shadow significantly stronger on left detector, turn right.IF (timeLeft > timeRight + difference) THENmaneuver = RotateRightGOSUB Servos_And_Sensors' Shadow significantly stronger on right detector, turn left.ELSEIF (timeRight > timeLeft + difference) THENmaneuver=RotateLeftGOSUB Servos_And_SensorsELSEmaneuver=ForwardGOSUB Servos_And_SensorsENDIFRETURN'

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[noparse][[/noparse] Subroutine -Test_Photoresistors]

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Test_Photoresistors:HIGH 2' Left RC time measurement.PAUSE 3RCTIME 2,1,timeleftHIGH 3 ' Right RC time measurement.PAUSE 3RCTIME 3,1,timeRightRETURN

makopolo

I dont understand in the "Look_About" subroutine why you are dividing by 6.

You are probably never executing the maneuver= Foward command

I dont understand what you mean by "gets within 2 feet of the light ", is the ligth at a constant location of are you movind it to direct the bot?

ltmhall

The light is in a fixed position and the 6 comes from the "avoid shadows" program in the robotics with the Boe Bot manual.