Boe-Bot with Whiskers

Parallax Boe-Bot roaming around with whiskers to avoid obstacles.

Video

Hardware

• Parallax Boe-Bot
• 2 x Servo Motors [pins 12 and 13]
• 2 x Wire Whiskers [pins 5 and 7]
• 2 x Red LEDs (with suitable resistors as in the Student Guide) [pins 1 and 10]
• Piezo Speaker [pin 4]

Listing

Download bs2 file

' Roam with Whiskers

' {$STAMP BS2}
' {$PBASIC 2.5}

DEBUG "Program Start..."

speed      VAR Byte ' speed + or - difference from 750
distance   VAR Word ' distance to move (mm)
direction  VAR Nib  ' direction 3 = forward/1 = backward
turn       VAR Byte ' turn rate 120 = no turn 240 = hard right, 0 = hard left

repeat     VAR Byte ' repeat, used for various features
counter    VAR Word ' count, used for various features

' start warning sound
PAUSE 500 : repeat = 4 : GOSUB alarm

DO
  IF (IN5 = 0) AND (IN7 = 0) THEN ' Both whiskers detect obstacle
    HIGH 1
    HIGH 10
    distance = 180 : speed = 30 : direction = 1 : turn = 120 : GOSUB move
    distance = 120 : speed = 30 : direction = 3 : turn = 0 : GOSUB move
  ELSEIF (IN5 = 0) THEN ' Left whisker contacts
    LOW 1
    HIGH 10
    distance = 130 : speed = 30 : direction = 1 : turn = 120 : GOSUB move
    distance = 50 : speed = 30 : direction = 1 : turn = 80 : GOSUB move
    distance = 50 : speed = 30 : direction = 3 : turn = 160 : GOSUB move
  ELSEIF (IN7 = 0) THEN ' Right whisker contacts
    HIGH 1
    LOW 10
    distance = 130 : speed = 30 : direction = 1 : turn = 120 : GOSUB move
    distance = 50 : speed = 30 : direction = 1 : turn = 160 : GOSUB move
    distance = 50 : speed = 30 : direction = 3 : turn = 80 : GOSUB move
  ELSE ' Both whiskers 1, no contacts
    LOW 1
    LOW 10
    distance = 10 : speed = 30 : direction = 3 : turn = 120 : GOSUB move
  ENDIF ' and check again
LOOP

END

' sub programs
alarm:
  FOR counter = 1 TO repeat
    FREQOUT 4, 100, 3000
    PAUSE 200
  NEXT
  RETURN

move:
  repeat = (41 * distance) / 130
  FOR counter = 1 TO repeat
    PULSOUT 13, 750 + ((speed + (turn - 120)) * (direction - 2))
    PULSOUT 12, 750 - ((speed - (turn - 120)) * (direction - 2))
    PAUSE 20
  NEXT
  RETURN