3. Maqueen motors

3.1. Set up the buggy

class MaqueenMotors
Set up the buggy’s motors for use.
Use buggy = maqueen.MaqueenMotors() to use the motor on the buggy.
The code below imports the maqueen module and sets up the motors.
from microbit import *
import maqueen


# setup buggy
buggy = maqueen.MaqueenMotors()

3.2. Duration parameter

The Buggy methods that drive the motors have a duration parameter.
The duration parameter specifies how long the motor runs for.
The default duration is None. If the duration is None or is not specified the motor will run continuously until another command is sent to it.
e.g. using the duration parameter: buggy.forwards(1, duration=5000) the buggy stops after 5 sec.
e.g. not using the duration parameter: buggy.forwards(1) the buggy runs forwards continuously.

3.3. Independent motor control

The left and right motors can be controlled independently using the four methods below:
left_motor(speed=1, duration=None) runs the left motor.
right_motor(speed=1, duration=None) runs the right motor.
stop_left() stops the left motor.
stop_right() stops the right motor.

3.3.1. left_motor

left_motor(speed=1, duration=None)
Make the left motor run.
speed values are integers from -5 to 5.
Default speed is 1.
If speed < 0 the motor turns the wheel backwards.
duration values are integers above 0.
Default duration is None.
The motor will stop after a given duration in milliseconds.
If the duration is None, the motor runs without stopping.
left_motor() and left_motor(1) and left_motor(speed=1) all set the speed to 1.
left_motor(2, 3000) and left_motor(2, duration=3000) and left_motor(speed=2, duration=3000) all run the left motor at speed 2 for 3 sec.
The code below, using left_motor(5), runs the left motor at full speed.
from microbit import *
import maqueen


# setup buggy
buggy = maqueen.MaqueenMotors()

buggy.left_motor(5)
The code below, using left_motor(2, 5000), runs the left motor at speed 2 for 5 sec.
from microbit import *
import maqueen


# setup buggy
buggy = maqueen.MaqueenMotors()

buggy.left_motor(2, 5000)

3.3.2. right_motor

right_motor(speed=1, duration=None)
Make the left motor run.
speed values are integers from -5 to 5.
Default speed is 1.
If speed < 0 the motor turns the wheel backwards.
duration values are integers above 0.
Default duration is None.
The motor will stop after a given duration in milliseconds.
If the duration is None, the motor runs without stopping.
right_motor() and right_motor(1) and right_motor(speed=1) all set the speed to 1.
right_motor(2, 4000) and right_motor(2, duration=4000) and right_motor(speed=2, duration=4000) all run the right motor at speed 2 for 4sec.
The code below, using right_motor(speed=4, duration=3000), runs the right motor at speed 4 for 3 sec.
from microbit import *
import maqueen


# setup buggy
buggy = maqueen.MaqueenMotors()

buggy.right_motor(speed=4, duration=3000)
The code below, using right_motor(-5), runs the right motor backwards at full speed.
from microbit import *
import maqueen


# setup buggy
buggy = maqueen.MaqueenMotors()

buggy.right_motor(-5)

3.3.3. stop_left

stop_left()
Stop the left motor.
The code below runs the left motor continuously during the sleep of 2 sec then stops it.
from microbit import *
import maqueen


# setup buggy
buggy = maqueen.MaqueenMotors()

buggy.left_motor()
sleep(2000)
buggy.stop_left()

3.3.4. stop_right

stop_right()
Stop the right motor.
The code below runs the right motor continuously during the sleep then stops it.
from microbit import *
import maqueen


# setup buggy
buggy = maqueen.MaqueenMotors()

buggy.right_motor(4)
sleep(2000)
buggy.stop_right()

3.4. Stop both motors

stop()
Stop both motors.
The code below runs the left motor at speed 5 and the right motor at speed 2, then after 1500ms stops them both.
from microbit import *
import maqueen


# setup buggy
buggy = maqueen.MaqueenMotors()

buggy.left_motor(5)
buggy.right_motor(2)
sleep(1500)
buggy.stop()

Tasks

  1. Write code to drive the left motor at speed 2 for 1 second, stop it, run the right motor at speed 2 for 1 sec then stop it.

  2. Write code to drive the right motor at speed 3 while the left motor runs at speed 2 for 3 sec then stop it.

  3. Write code to drive the left motor at speed 3 while the right motor runs at speed 2 for 3 sec then stop it.

  4. Write code that drives the left side faster than the right side then the right side faster the left side so that it zig zags for 5 sec then stop it.

  5. Write code so that the buggy repetitively zig zags forwards for 5 zigs and zags then forwards forwards for 5 zigs and zags.

  6. Modify the zig zag code so that it uses variables for the 2 motor speeds, the number of zig zags forwards and backward, and the time for each zig and zag.

3.5. forwards and backwards

The left and right motors can be run so that the buggy moves forwards or backwards in a straight line:
forwards(speed=1, duration=None)
backwards(speed=1, duration=None)

3.5.1. forwards

forwards(speed=1, duration=None)
Drive the buggy forward.
speed values are integers from 0 to 5.
Default speed is 1.
duration values are integers above 0.
Default duration is None.
The motor will stop after a given duration in milliseconds.
The code below, drives the buggy forwards at speed 5 for 4 secs.
from microbit import *
import maqueen


# setup buggy
buggy = maqueen.MaqueenMotors()

buggy.forwards(speed=5, duration=4000)

3.5.2. backwards

backwards(speed=1, duration=None)
Drive the buggy backwards.
speed values are integers from 0 to 5.
Default speed is 1.
duration values are integers above 0.
Default duration is None.
The motor will stop after a given duration in milliseconds.
If the duration is None, the motor runs without stopping.
The code below drives the buggy backwards at speed 5 for 3 secs.
from microbit import *
import maqueen


# setup buggy
buggy = maqueen.MaqueenMotors()

buggy.backwards(5, 3000)

Tasks

  1. Write code to drive the buggy forwards at speed 3 for 3 seconds.

  2. Write code to drive the buggy backwards at speed 1 for 2 seconds.

  3. Write code to drive the buggy forwards at speed 1 for 3 seconds then backwards at speed 1 for 3 seconds.

3.6. Turning

The left and right motors are adjusted to turn the buggy with a given turn tightness:
left(tightness=5, duration=None)
right(tightness=5, duration=None)
When turning left, the left wheel is slowed based on the tightness value.
When turning right, the right wheel is slowed based on the tightness value.
The turning tightness is greatest with a value of 5.

3.6.1. left

left(tightness=5, duration=None)
Drive the buggy to the left.
tightness values are integers from 1 to 5
Default tightness is 5 (a tight turn).
duration values are integers above 0.
Default duration is None.
The motor will stop after a given duration in milliseconds.
If the duration is None, the motor runs without stopping, until another command is sent to the motor.
The code below, left(tightness=5, duration=4000), turns the buggy left through a tight turn for 4 secs.
from microbit import *
import maqueen


# setup buggy
buggy = maqueen.MaqueenMotors()

buggy.left(tightness=5, duration=4000)

Tasks

  1. Write code to drive the buggy to the left at tightness 3 for 5 seconds.

  2. Write code to drive the buggy to the left at tightness 1 for 5 seconds.

  3. Write code to drive the buggy to the left at increasing tightness. Use a for-loop to change the tightness from 1 to 5, with each turn lasting for 2 seconds.

3.7. Spinning

Spin the buggy to the left or right at the chosen speed using:
spin_left(speed=1, duration=None)
spin_right(speed=1, duration=None)
When spining left, the left wheel goes forwards while the right wheel goes forward.
When spining right, the right wheel goes forwards while the left wheel goes forward.

3.7.1. spin left

spin_left(speed=1, duration=None)
Spin the buggy on the spot.
speed values are integers from 0 to 5.
Default speed is 1.
duration values are integers above 0.
Default duration is None.
The motor will stop after a given duration in milliseconds.
If the duration is None, the motor runs without stopping, until another command is sent to the motor.
spin_left() and spin_left(1) and spin_left(speed=1) all spin the buggy to the left at speed 1.
spin_left(3, 2000) and spin_left(3, duration=2000) and spin_left(speed=3, duration=2000) all spin the buggy to the left at speed 3 for 2 secs.

3.7.2. spin right

spin_right(speed=1, duration=None)
Spin the buggy on the spot.
speed values are integers from 0 to 5.
Default speed is 1.
duration values are integers above 0.
Default duration is None.
The motor will stop after a given duration in milliseconds.
If the duration is None, the motor runs without stopping, until another command is sent to the motor.
The code below, spin_right(2, 4000), spins the buggy to the right at speed 2 for 4 secs.
from microbit import *
import maqueen


# setup buggy
buggy = maqueen.MaqueenMotors()

buggy.spin(2, 'right', 4000)

Tasks

  1. Write code to spin the buggy to the left at speed 4 for 5 seconds.

  2. Write code to spin the buggy to the right at speed 2 for 3 seconds.

  3. Write code to spin the buggy to the left for 3 seconds then to right for 3 seconds at speed 4.

  4. Write code to drive the buggy in a polygonal path (many straight sides) by combining short drives forwards with short spins.