Boebot project problem
MikeToreno
Posts: 3
Hello everyone,
I'm Mike and I'm a student.
This month we had to create a boebot program using photoresistors and ir led. The robot should follow an electrical tape stripe with the ir led on a table. The robot must also run his program only when the photoresistor detects a high level of light, in order to avoid failing down from the table.
In my program ( a mix of stripefollowingboebot and a modified flashlightcontrolledboebot) the robot run perfectly until the border of the table. Normally it should completely stop itself, but in my case it continues to produce little movements forward and backward): I 've also tried to add a counter out of the DO-LOOP, but uselessly. What I've to do?
Thanks,:smilewinkgrin:
sorry for my bad english.
This is the program:
I'm Mike and I'm a student.
This month we had to create a boebot program using photoresistors and ir led. The robot should follow an electrical tape stripe with the ir led on a table. The robot must also run his program only when the photoresistor detects a high level of light, in order to avoid failing down from the table.
In my program ( a mix of stripefollowingboebot and a modified flashlightcontrolledboebot) the robot run perfectly until the border of the table. Normally it should completely stop itself, but in my case it continues to produce little movements forward and backward): I 've also tried to add a counter out of the DO-LOOP, but uselessly. What I've to do?
Thanks,:smilewinkgrin:
sorry for my bad english.
This is the program:
' {$STAMP BS2}
' {$PBASIC 2.5}
DEBUG "Program Running!"
'----------------[Constantes]---------------------------------------------
Kpl CON 25
Kpr CON -25
SetPoint CON 3
CenterPulse CON 750
LeftAmbient CON 156
RightAmbient CON 160
LeftBright CON 59
RightBright CON 53
LeftThreshold CON LeftBright + LeftAmbient / 2 * 5 / 8
RightThreshold CON RightBright + RightAmbient / 2 * 5 / 8
'----------------[Variables]------------------------------------------------
freqSelect VAR Nib
irFrequency VAR Word
irDetectRight VAR Bit
irDetectLeft VAR Bit
distanceLeft VAR Nib
distanceRight VAR Nib
pulseleft VAR Word
pulseright VAR Word
timeLeft VAR Word
timeRight VAR Word
counter VAR Nib
'----------------[Initialization]---------------------------------------------
FREQOUT 4, 2000, 3000
counter = 1
'----------------[Main Routine]--------------------------------------------
IF (counter < 5) THEN
DO
GOSUB Test_Photoresistors
GOSUB Navigate
LOOP
ELSE
PULSOUT 13,750
PULSOUT 12,750
ENDIF
END
'----------------[Subroutines]---------------------------------------------
Get_Ir_Distances:
distanceLeft = 0
distanceRight = 0
FOR freqSelect = 0 TO 4
LOOKUP freqSelect,[37500,38250,39500,40500,41500], irFrequency
FREQOUT 8,1, irFrequency
irDetectLeft = IN9
distanceLeft = distanceLeft + irDetectLeft
FREQOUT 2,1, irFrequency
irDetectRight = IN0
distanceRight = distanceRight + irDetectRight
NEXT
RETURN
Send_Pulse:
PULSOUT 13,pulseleft
PULSOUT 12,pulseright
PAUSE 5
RETURN
Test_Photoresistors:
HIGH 6
PAUSE 3
RCTIME 6,1, timeLeft
HIGH 3
PAUSE 3
RCTIME 3,1, timeRight
RETURN
Navigate:
IF (timeLeft > LeftThreshold)AND (timeRight > RightThreshold) THEN
counter = counter + 1
PULSOUT 13,750
PULSOUT 12,750
ELSEIF (timeLeft > LeftThreshold) THEN
counter = counter + 1
PULSOUT 13,750
PULSOUT 12,750
ELSEIF (timeRight > RightThreshold) THEN
counter = counter + 1
PULSOUT 13,750
PULSOUT 12,750
ELSE
GOSUB Get_Ir_Distances
pulseleft = SetPoint - distanceLeft * Kpl + CenterPulse
pulseright = SetPoint - distanceRight * Kpr + CenterPulse
GOSUB Send_Pulse
ENDIF
PAUSE 20
RETURN
Comments
IF (counter < 5) THEN
DO
GOSUB Test_Photoresistors
GOSUB Navigate
LOOP
ELSE
PULSOUT 13,750
PULSOUT 12,750
PAUSE 20
ENDIF
END
You don't need one in between two consecutive pulsouts (as shown).
Also, are you certain that your servos are stopped at pulsout 750? That's a general average number, yours may be 738 and 761. Experiment!
That's not quite right. You want to put in a PAUSE statement with a value such that the time from the beginning of one pulse to the beginning of the next is 20 milliseconds (as seen by each servo).
Your first subroutine, Test_Photoresistors, takes a minimum of six and probably more like eight milliseconds to execute. The next subroutine, Navigate, is going to take 3.0 milliseconds just to send the pulses. Add in a couple more milliseconds for executing the other commands and you have about 13 milliseconds total. The appropriate PAUSE time would then be about 7.
When your counter reaches five those subroutines will be skipped and a longer PAUSE statement is in order. The PAUSE 20 is fine there but a Pause 17 would be more precise because the two PULSOUTS consume at least three milliseconds.
The servos may be hunting at the end because they are not receiving any pulses and will be sensitive to other stray signals. Use a loop to keep refreshing the pulses.
Or, more likely, it could be because there is no way to exit from the first loop. Once the counter is tested and found to be less than five you become stuck in the loop, counter is never tested again.
Here is how I would do it, remove the PAUSE 20 from Navigate, remove the PAUSE 5 from Send_Pulse and then change your main loop to this;
DO IF (counter < 5) THEN GOSUB Test_Photoresistors GOSUB Navigate PAUSE 7 ELSE PULSOUT 13,750 PULSOUT 12,750 PAUSE 17 ENDIF LOOP ENDRich H
@Mike: Do you have any idea what section of the program is causing the twitching problem? It may be different than you suspect.... Try adding some different DEBUG statements and run the program while hooked up to a laptop.
You are welcome.
Check his DO..LOOP, there is no exit.
Rich H
The solution proposed by Rich worked perfecty......the robot avoided the table edge perfecty and also it didn't twitch.
I've only to hope it will works correctly for the test, too.
Thanks, Mike
Rich H