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• Walking

  deʃhipu • 03/09/2017 at 14:59 • 0 comments

  After a few tests with walking, I decided to not give it a huge head after all. I tried a number of different heads (including several acrylic globes from a crafts store, a doll's head and a lightbulb) and finally settled on a cardboard outline. This is something that an 11-years old can see and say "I could do that!"

  For now I used the same code for walking as the #Micro:Bob (I just had to swap some pins and adjust trims), but I want to make it controlled from a second Micro:bit.

  import microbit
  
  
  class Servo:
      def __init__(self, pin, trim=0):
          self.pin = pin
          self.trim = trim
          self.position = 90
          self.set_period()
  
      def set_period(self):
          self.pin.set_analog_period(20)
          self.write(self.position)
          microbit.sleep(80)
          self.pin.set_analog_period(20)
          self.write(self.position)
          microbit.sleep(80)
          self.pin.write_analog(0)
  
      def write(self, degrees):
          self.pin.write_analog(int(25 + 100 * degrees / 180 + self.trim))
          self.position = degrees
  
      def move(self, degrees, delay=5):
          if degrees > self.position:
              step = 1
          else:
              step = -1
          for position in range(self.position, degrees, step):
              self.write(position)
              microbit.sleep(delay)
  
  
  class Robot:
      NORMAL_FACE = microbit.Image(
          "42024\n"
          "90009\n"
          "00000\n"
          "61016\n"
          "27972\n"
      )
      RIGHT_FACE = microbit.Image(
          "24024\n"
          "09009\n"
          "00000\n"
          "81001\n"
          "28952\n"
      )
      LEFT_FACE = microbit.Image(
          "42042\n"
          "90090\n"
          "00000\n"
          "10018\n"
          "25983\n"
      )
  
      def __init__(self):
          self.feet_servo = Servo(microbit.pin2, -2)
          self.left_servo = Servo(microbit.pin1, 4)
          self.right_servo = Servo(microbit.pin0, 4)
          microbit.display.show(self.NORMAL_FACE)
  
      def right_step(self):
          microbit.display.show(self.RIGHT_FACE)
          self.feet_servo.move(120)
          self.left_servo.move(60)
          self.right_servo.move(60)
          self.feet_servo.move(90)
  
      def left_step(self):
          microbit.display.show(self.LEFT_FACE)
          self.feet_servo.move(60)
          self.right_servo.move(120)
          self.left_servo.move(120)
          self.feet_servo.move(90)
  
      def right_half_step(self):
          microbit.display.show(self.NOLRMAL_FACE)
          self.feet_servo.move(120)
          self.left_servo.move(90)
          self.right_servo.move(90)
          self.feet_servo.move(90)
  
      def left_half_step(self):
          microbit.display.show(self.NORMAL_FACE)
          self.feet_servo.move(60)
          self.right_servo.move(90)
          self.left_servo.move(90)
          self.feet_servo.move(90)
  
  
      def walk(self, steps=1):
          step = 0
          for step in range(steps - 1):
              if step % 2:
                  self.left_step()
              else:
                  self.right_step()
          if step % 2:
              self.right_half_step()
          else:
              self.left_half_step()
  
  
  robot = Robot()
  robot.walk(8)
  

• The Base

  deʃhipu • 03/07/2017 at 16:40 • 0 comments

  So this is a successor of the #Micro:Bob robot, that would be a little less "gangsta". I designed a PCB for attaching everything together -- the micro:bit, the servos and the battery -- so that you don't have an ungodly mess of wires held together with two-sided tape. I also left some extra holes in the PCB to which you can solder paperclips, to build on top of it and make it a little more interesting.

  I found a nice method of mounting the micro:bit to the PCB without using the bulky edge connection -- just use loops of wire made out of paperclips, and plastic bolts (to not damage the micro:bit). The servos fit right into the slots -- I just made the screw holes a bit too tight, had to enlarge them a bit later. The battery holder is still attached to the backs of the servos with a two-sided tape -- there is no room on the board for a different way of attaching it, unfortunately.

  In hindsight, I should have made more sockets for the servos -- letting you to plug several servos to the same pin, so they move together, so that you can make hands that move together with the legs, etc. -- maybe in the next version.

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