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motor_rotate.rst

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2. Get the Motor Rotating

Principle of Motor Rotation

As shown in cpn_tt_motor, the motors of the Pico 4WD Car are driven by the TC1508S chips. The control pins corresponding to the 4 motors and the direction of rotation are shown below.

Motor-Pin List
Motor PinA PinB
Left Front GP17 GP16
Right Front GP15 GP14
Left Rear GP13 GP12
Right Rear GP11 GP10
Motor Work
PinA PinB Work
H L Rotate Clockwise(CW)
L H Rotate Counter-clockwise(CCW)
H H Stop

Now let's start writing the script to see how the motors turn.

Motor Turns Clockwise

  1. Take Right Rear Motor for example, it is controlled by GP11 and GP10. Write low for GP11 and high for GP10.

    import machine

pinA = machine.Pin(11, machine.Pin.OUT)
pinB = machine.Pin(10, machine.Pin.OUT)

pinA.low()
pinB.high()
  2. Copy the above code into Thonny or open the motor_2_cw.py under the path of pico_4wd_car-v2.0\examples\learn_modules.

  3. Use a micro USB cable to connect the Pico to your computer and select the "MicroPython (Raspberry Pi Pico) COMxx" interpreter.

    image

  4. Click button or simply press F5 to run it.

  5. Start the Pico 4WD car.

    • When first used or when the battery cable is unplugged, Pico RDP will activate its over-discharge protection circuitry(Unable to get power from battery).
    • Therefore, you'll need to plug in a Type-C cable for about 5 seconds to release the protection status.

    • At this time look at the battery indicators, if both battery indicators are off, please continue to plug in the Type-C cable to charge the battery.

      image

  6. As you hold the Pico 4WD Car up high, you will be able to see the right rear motor turning clockwise.

Next you can run the following scripts in sequence to see what happens.

Stop the Motor

Write two high levels, motor stops.

import machine

pinA = machine.Pin(11, machine.Pin.OUT)
pinB = machine.Pin(10, machine.Pin.OUT)

pinA.high()
pinB.high()

Motor Turns Counter-clockwise

Reversing the high and low levels, the motor will rotate counterclockwise.

import machine

pinA = machine.Pin(11, machine.Pin.OUT)
pinB = machine.Pin(10, machine.Pin.OUT)

pinA.high()
pinB.low()

Stop 4 Motors

Stop all motors.

import machine

for i in range(10,18):
    pin = machine.Pin(i, machine.Pin.OUT)
    pin.high()