Nesting loops in Boe-Bot whisker navigation

Robostooge · 2006-01-23 01:36

Greetings. We are new to Basic Stamp and the forum. We are going through the Boe-Bot Manual, and have a question about using whisker navigation. We used the code from the manual (Example Program: RoamingWithWhiskers.bs2, page 192 of the Acrobat version). The whisker navigation works great, and we decided to add flashing LED’S. (LED’S continually flash as the Boe- Bot moves)
·
We used the following code to flash LED’s
·
Do
High 1························· ‘LED ·1 on
High 10······················· ‘LED 2 on
Pause 500
Low 1························· ‘LED off
High 10······················· ‘LED off
Pause 500
Loop
·
This code works on it’s own, but we can’t seem to figure out where to put it without it messing up the main program or the subroutines.
·
In other words, we want the flashing LED subroutine to be continuously executed as the whisker decision trees for the navigation work independently.
·
We’ve tried it at every place in the program we can think of, and it messes up the subroutines.
·
Are we missing something basic or is this actually more complicated to do than we think?
·
PS we did not write out the code from the book to save space, but can if that will help get the question answered.

Any ideas?

Many thanks

Andy Lindsay (Parallax) · 2006-01-23 03:40

Later in the book, example programs that send servo pulses from only once per main loop will make it easier to add this feature.·

Recall from Chapter 2, Activity #6 that servo pulses repeat about every 25 ms.· To delay for 0.5 seconds, this program's Flash_Leds subroutine·counts up to 20 servo pulses (20 x .025 s = 0.5 s), then changes the state of the LEDs.· The Flash_Leds subroutine is called from everywhere the program delivers a servo pulse.· More importantly, the program is doing it from inside the various FOR...NEXT loops.· If those Flash_Leds subroutine calls were outside the FOR...NEXT loops, there would be interruptions in the flashing every time a maneuver was executed.

BTW, another interesting modification is to light up the left LED while the Boe-Bot is avoiding an object on the left, the right LED while the Boe-Bot is avoiding an object on its right, etc.

' -----[noparse][[/noparse] Title ]--------------------------------------------------------------
' Robotics with the Boe-Bot - RoamingWithWhiskers.bs2
' Boe-Bot uses whiskers to detect objects, and navigates around them.
 
' {$STAMP BS2}                               ' Stamp directive.
' {$PBASIC 2.5}                              ' PBASIC directive.
 
DEBUG "Program Running!"
 
' -----[noparse][[/noparse] Variables ]----------------------------------------------------------
 
pulseCount     VAR     Byte                  ' FOR...NEXT loop counter.
counter        VAR     Byte
 
' -----[noparse][[/noparse] Initialization ]-----------------------------------------------------
 
FREQOUT 4, 2000, 3000                        ' Signal program start/reset.
LOW 1
LOW 10
 
' -----[noparse][[/noparse] Main Routine ]-------------------------------------------------------
 
DO
[color=#000000]  IF (IN5  = 0) AND (IN7 = 0) THEN           ' Both whiskers detect obstacle[/color]
[color=#000000]    GOSUB Back_Up                            ' Back up & U-turn (left twice)[/color]
[color=#000000]    GOSUB Turn_Left[/color]
[color=#000000]    GOSUB Turn_Left[/color]
[color=#000000]  ELSEIF (IN5  = 0) THEN                     ' Left whisker contacts[/color]
[color=#000000]    GOSUB Back_Up                            ' Back up & turn right[/color]
[color=#000000]    GOSUB Turn_Right[/color]
[color=#000000]  ELSEIF (IN7  = 0) THEN                     ' Right whisker contacts[/color]
[color=#000000]    GOSUB Back_Up                            ' Back up & turn left[/color]
[color=#000000]    GOSUB Turn_Left[/color]
[color=#000000]  ELSE                                       ' Both whiskers 1, no contacts[/color]
[color=#000000]    GOSUB Forward_Pulse                      ' Apply a forward pulse[/color]
[color=#000000]  ENDIF                                      ' and check again[/color]
LOOP
 
' -----[noparse][[/noparse] Subroutines ]--------------------------------------------------------
 
Forward_Pulse:                               ' Send a single forward pulse.
[color=#000000]  PULSOUT 13,850[/color]
[color=#000000]  PULSOUT 12,650[/color]
[color=#000000]  PAUSE 20[/color]
[color=#000000]  GOSUB Flash_Leds
  RETURN[/color]
 
Turn_Left:                                   ' Left turn, about 90-degrees.
[color=#000000]  FOR pulseCount = 0 TO 20[/color]
[color=#000000]    PULSOUT 13, 650[/color]
[color=#000000]    PULSOUT 12, 650[/color]
[color=#000000]    PAUSE 20[/color]
[color=#000000]    GOSUB Flash_Leds
  NEXT[/color]
[color=#000000]  RETURN[/color]
 
Turn_Right:
[color=#000000]  FOR pulseCount = 0 TO 20                   ' Right turn, about 90-degrees.[/color]
[color=#000000]    PULSOUT 13, 850[/color]
[color=#000000]    PULSOUT 12, 850[/color]
[color=#000000]    PAUSE 20[/color]
[color=#000000]    GOSUB Flash_Leds
  NEXT[/color]
[color=#000000]  RETURN[/color]
 
Back_Up:                                     ' Back up.
[color=#000000]  FOR pulseCount = 0 TO 40[/color]
[color=#000000]    PULSOUT 13, 650[/color]
[color=#000000]    PULSOUT 12, 850[/color]
[color=#000000]    PAUSE 20[/color]
[color=#000000]    GOSUB Flash_Leds
  NEXT[/color]
[color=#000000]  RETURN[/color]
 
Flash_Leds:
 
  counter = counter + 1
  IF counter = 20 THEN
    counter = 1
    TOGGLE 1
    TOGGLE 10
  ENDIF
 
  RETURN

Post Edited (Andy Lindsay (Parallax)) : 1/23/2006 4:05:00 AM GMT

Robostooge · 2006-01-23 22:14

Thank you for your advice. I used the program you listed above and now my Boe-Bot is roaming around the room with flashing LED's!

Nesting loops in Boe-Bot whisker navigation

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