Chapter 15 Relay & Motor
=========================
In this chapter, we will learn a kind of special switch module, relay module.

Project 15.1 Control Motor with Potentiometer
------------------------------------------------
Control the direction and speed of the motor with a potentiometer.

Component List
^^^^^^^^^^^^^^^
- ESP32-S3-WROOM x1
- GPIO Extension Board x1
- 830 Tie-Points Breadboard x1
- L293D x1
- 9V Battery Connector x1
- Potentiometer(10k) x1
- Motor & Fan x1
- Jumper Wire

Connect
^^^^^^^^^
Use caution when connecting this circuit, because the DC motor is a high-power 
component, do not use the power provided by the ESP32-S3 to power the motor directly, 
which may cause permanent damage to your ESP32-S3! The logic circuit can be powered 
by the ESP32-S3 power or an external power supply, which should share a common 
ground with ESP32-S3.

.. image:: img/connect/15.png

Note: the motor circuit uses A large current, about 0.2-0.3A without load.We rec
ommend that you use a 9V battery to power the extension board.

Code
^^^^^^^
Move the program folder :file:`Super_Starter_Kit_for_ESP32_S3/Python/Python_Codes` to disk(D) in advance with the path of “D:/Micropython_Codes”. 
Open “Thonny”, click :file:`This computer/D:/Micropython_Codes/15.2_Motor_And_Driver` and double click “Motor_And_Driver.py”.

**15.1_Motor_And_Driver**

.. image:: img/software/15.1.png

Click “Run current script”, Rotate the potentiometer clockwise, and the motor will 
gradually accelerate and rotate in one direction. Rotate the potentiometer in the 
opposite direction, and the motor will decelerate, stop, and then rotate in the 
other direction.

.. image:: img/phenomenon/15.1.png

Code
^^^^^^
The following is the program code:

.. code-block:: python

    from machine import ADC,Pin,PWM
    import time
    import math

    in1Pin=Pin(13, Pin.OUT)
    in2Pin=Pin(14, Pin.OUT)

    enablePin=Pin(12, Pin.OUT)
    pwm=PWM(enablePin,10000)

    adc=ADC(Pin(1))
    adc.atten(ADC.ATTN_11DB)
    adc.width(ADC.WIDTH_12BIT)

    def driveMotor(dir,spd):
        if dir:
            in1Pin.value(1)
            in2Pin.value(0)
        else :
            in1Pin.value(0)
            in2Pin.value(1)
        pwm.duty(spd)
        
    try:
        while True:
            potenVal = adc.read()
            rotationSpeed = potenVal - 2048
            if (potenVal > 2048):
                rotationDir = 1;
            else:
                rotationDir = 0;
            rotationSpeed=int(math.fabs((potenVal-2047)//2)-1)
            driveMotor(rotationDir,rotationSpeed)
            time.sleep_ms(10)
    except:
        pwm.deinit()