3.1.4 Smart Fan

Introduction

In this project, we will use motors, buttons and thermistors to make a manual + automatic smart fan whose wind speed is adjustable.

Required Components

In this project, we need the following components.

Schematic Diagram

T-Board Name	physical	wiringPi	BCM
GPIO17	Pin 11	0	17
GPIO18	Pin 12	1	18
GPIO27	Pin 13	2	27
GPIO22	Pin 15	3	22
GPIO5	Pin 29	21	5
GPIO6	Pin 31	22	6
GPIO13	Pin 33	23	13

Experimental Procedures

Step 1: Build the circuit.

Note

The power module can apply a 9V battery with the 9V Battery Buckle in the kit. Insert the jumper cap of the power module into the 5V bus strips of the breadboard.

Step 2: Get into the folder of the code.

cd ~/raphael-kit/python-pi5

Step 3: Run.

sudo python3 3.1.4_SmartFan_zero.py

As the code runs, start the fan by pressing the button. Every time you press, 1 speed grade is adjusted up or down. There are 5 kinds of speed grades: 0~4. When set to the 4^th speed grade and you press the button, the fan stops working with a 0 wind speed.

Once the temperature goes up or down for more than 2℃, the speed automatically gets 1-grade faster or slower.

Code

Note

You can Modify/Reset/Copy/Run/Stop the code below. But before that, you need to go to source code path like raphael-kit/python-pi5. After modifying the code, you can run it directly to see the effect.

#!/usr/bin/env python3

from gpiozero import Motor, Button
from time import sleep
import ADC0834
import math

# Initialize GPIO pins for the button and motor control
BtnPin = Button(22)
motor = Motor(forward=5, backward=6, enable=13)

# Initialize the ADC0834 module for temperature sensing
ADC0834.setup()

# Initialize variables to track the motor speed level and temperatures
level = 0
currentTemp = 0
markTemp = 0

def temperature():
    """
    Reads and calculates the current temperature from the sensor.
    Returns:
        float: The current temperature in Celsius.
    """
    # Read analog value from the ADC0834 module
    analogVal = ADC0834.getResult()
    # Convert analog value to voltage and then to resistance
    Vr = 5 * float(analogVal) / 255
    Rt = 10000 * Vr / (5 - Vr)
    # Calculate temperature in Celsius
    temp = 1 / (((math.log(Rt / 10000)) / 3950) + (1 / (273.15 + 25)))
    Cel = temp - 273.15
    return Cel

def motor_run(level):
    """
    Adjusts the motor speed based on the specified level.
    Args:
        level (int): Desired motor speed level.
    Returns:
        int: Adjusted motor speed level.
    """
    # Stop the motor if the level is 0
    if level == 0:
        motor.stop()
        return 0
    # Cap the level at 4 for maximum speed
    if level >= 4:
        level = 4
    # Set the motor speed
    motor.forward(speed=float(level / 4))
    return level

def changeLevel():
    """
    Changes the motor speed level when the button is pressed and updates the reference temperature.
    """
    global level, currentTemp, markTemp
    print("Button pressed")
    # Cycle through levels 0-4
    level = (level + 1) % 5
    # Update the reference temperature
    markTemp = currentTemp

# Bind the button press event to changeLevel function
BtnPin.when_pressed = changeLevel

def main():
    """
    Main function to continuously monitor and respond to temperature changes.
    """
    global level, currentTemp, markTemp
    # Set initial reference temperature
    markTemp = temperature()
    while True:
        # Continuously read current temperature
        currentTemp = temperature()
        # Adjust motor level based on temperature difference
        if level != 0:
            if currentTemp - markTemp <= -2:
                level -= 1
                markTemp = currentTemp
            elif currentTemp - markTemp >= 2:
                if level < 4:
                    level += 1
                markTemp = currentTemp
        # Run the motor at the adjusted level
        level = motor_run(level)

# Run the main function and handle KeyboardInterrupt
try:
    main()
except KeyboardInterrupt:
    # Stop the motor when the script is interrupted
    motor.stop()

Code Explanation

1. Imports classes for managing a motor and a button, and the sleep function for introducing pauses. Additionally, it imports the ADC0834 library for temperature sensing and the math library for mathematical calculations.

   #!/usr/bin/env python3
   
   from gpiozero import Motor, Button
   from time import sleep
   import ADC0834
   import math
   

2. Sets up the button on GPIO pin 22 and configures the motor with specific GPIO pins for control. Initializes the ADC0834 module for temperature measurement. Also, initializes variables to monitor the motor speed level and temperatures.

   # Initialize GPIO pins for the button and motor control
   BtnPin = Button(22)
   motor = Motor(forward=5, backward=6, enable=13)
   
   # Initialize the ADC0834 module for temperature sensing
   ADC0834.setup()
   
   # Initialize variables to track the motor speed level and temperatures
   level = 0
   currentTemp = 0
   markTemp = 0
   

3. Defines a function to read and calculate the temperature from the sensor, converting the readout to Celsius.

   def temperature():
       """
       Reads and calculates the current temperature from the sensor.
       Returns:
           float: The current temperature in Celsius.
       """
       # Read analog value from the ADC0834 module
       analogVal = ADC0834.getResult()
       # Convert analog value to voltage and then to resistance
       Vr = 5 * float(analogVal) / 255
       Rt = 10000 * Vr / (5 - Vr)
       # Calculate temperature in Celsius
       temp = 1 / (((math.log(Rt / 10000)) / 3950) + (1 / (273.15 + 25)))
       Cel = temp - 273.15
       return Cel
   

4. Introduces a function to adjust the motor speed according to the specified level.

   def motor_run(level):
       """
       Adjusts the motor speed based on the specified level.
       Args:
           level (int): Desired motor speed level.
       Returns:
           int: Adjusted motor speed level.
       """
       # Stop the motor if the level is 0
       if level == 0:
           motor.stop()
           return 0
       # Cap the level at 4 for maximum speed
       if level >= 4:
           level = 4
       # Set the motor speed
       motor.forward(speed=float(level / 4))
       return level
   

5. Implements a function to change the motor speed level manually using a button, and binds this function to the button’s press event.

   def changeLevel():
       """
       Changes the motor speed level when the button is pressed and updates the reference temperature.
       """
       global level, currentTemp, markTemp
       print("Button pressed")
       # Cycle through levels 0-4
       level = (level + 1) % 5
       # Update the reference temperature
       markTemp = currentTemp
   
   # Bind the button press event to changeLevel function
   BtnPin.when_pressed = changeLevel
   

6. The main function, designed to continually adjust the motor speed in response to temperature fluctuations, remains to be implemented.

   def main():
       """
       Main function to continuously monitor and respond to temperature changes.
       """
       global level, currentTemp, markTemp
       # Set initial reference temperature
       markTemp = temperature()
       while True:
           # Continuously read current temperature
           currentTemp = temperature()
           # Adjust motor level based on temperature difference
           if level != 0:
               if currentTemp - markTemp <= -2:
                   level -= 1
                   markTemp = currentTemp
               elif currentTemp - markTemp >= 2:
                   if level < 4:
                       level += 1
                   markTemp = currentTemp
           # Run the motor at the adjusted level
           level = motor_run(level)
   

7. Runs the main function and ensures the motor stops if the script is interrupted.

   # Run the main function and handle KeyboardInterrupt
   try:
       main()
   except KeyboardInterrupt:
       # Stop the motor when the script is interrupted
       motor.stop()