1  # SPDX-FileCopyrightText: 2018 Dave Astels for Adafruit Industries
  2  #
  3  # SPDX-License-Identifier: MIT
  4  
  5  import time
  6  import random
  7  from adafruit_crickit import crickit
  8  
  9  LEFT = False
 10  RIGHT = True
 11  
 12  random.seed(int(time.monotonic()))
 13  ss = crickit.seesaw
 14  
 15  left_wheel = crickit.dc_motor_1
 16  right_wheel = crickit.dc_motor_2
 17  
 18  RIGHT_BUMPER = crickit.SIGNAL1
 19  LEFT_BUMPER = crickit.SIGNAL2
 20  CENTER_BUMPER = crickit.SIGNAL3
 21  
 22  ss.pin_mode(RIGHT_BUMPER, ss.INPUT_PULLUP)
 23  ss.pin_mode(LEFT_BUMPER, ss.INPUT_PULLUP)
 24  ss.pin_mode(CENTER_BUMPER, ss.INPUT_PULLUP)
 25  
 26  # These allow easy correction for motor speed variation.
 27  # Factors are determined by observation and fiddling.
 28  # Start with both having a factor of 1.0 (i.e. none) and
 29  # adjust until the bot goes more or less straight
 30  def set_right(speed):
 31      right_wheel.throttle = speed * 0.9
 32  
 33  def set_left(speed):
 34      left_wheel.throttle = speed
 35  
 36  
 37  # Uncomment this to find the above factors
 38  # set_right(1.0)
 39  # set_left(1.0)
 40  # while True:
 41  #     pass
 42  
 43  # Check for bumper activation and move away accordingly
 44  # Returns False if we got clear, True if we gave up
 45  def react_to_bumpers():
 46      attempt_count = 0
 47      # keep trying to back away and turn until we're free
 48      while True:
 49  
 50          # give up after 3 tries
 51          if attempt_count == 3:
 52              return True
 53  
 54          bumped_left = not ss.digital_read(LEFT_BUMPER)
 55          bumped_right = not ss.digital_read(RIGHT_BUMPER)
 56          bumped_center = not ss.digital_read(CENTER_BUMPER)
 57  
 58          # Didn't bump into anything, we're done here
 59          if not bumped_left and not bumped_right and not bumped_center:
 60              return False
 61  
 62          # If the middle bumper was triggered, randomly pick a way to turn
 63          if bumped_center:
 64              bumped_left |= random.randrange(10) < 5
 65              bumped_right = not bumped_left
 66  
 67          # Back away a bit
 68          set_left(-0.5)
 69          set_right(-0.5)
 70          time.sleep(0.5)
 71  
 72          # If we bumped on the left, turn to the right
 73          if bumped_left:
 74              set_left(1.0)
 75              set_right(0.0)
 76  
 77              # If we bumped on the right, turn left
 78          elif bumped_right:
 79              set_left(0.0)
 80              set_right(1.0)
 81  
 82              # time to turn for
 83          time.sleep(random.choice([0.2, 0.3, 0.4]))
 84          attempt_count += 1
 85  
 86  
 87  def tack(direction, duration):
 88      target_time = time.monotonic() + duration
 89      if direction == LEFT:
 90          set_left(0.25)
 91          set_right(1.0)
 92      else:
 93          set_left(1.0)
 94          set_right(0.25)
 95      while time.monotonic() < target_time:
 96          if not(ss.digital_read(LEFT_BUMPER) and
 97                 ss.digital_read(RIGHT_BUMPER) and
 98                 ss.digital_read(CENTER_BUMPER)):
 99              return react_to_bumpers()
100      return False
101  
102  
103  while True:
104      if tack(LEFT, 0.75):
105          break
106      if tack(RIGHT, 0.75):
107          break
108  
109  
110  set_left(0)
111  set_right(0)
112  
113  while True:
114      for _ in range(3):
115          crickit.drive_2.fraction = 1.0
116          time.sleep(0.1)
117          crickit.drive_2.fraction = 0.0
118          time.sleep(.2)
119      time.sleep(10.0)