### Lesson Plan: Understanding and Utilizing the Three-leaf Fan in Electronic Circuits
**Introduction**
In this lesson, we will explore the operational principles and practical applications of the Three-leaf Fan. Small electric fans are commonly used in electronics for cooling purposes, such as dissipating heat from electronic components, or for creating airflow in small spaces. By the end of this lesson, you will have a comprehensive understanding of how to use a three-leaf fan in your electronic projects, particularly with the Raspberry Pi Pico WH.
**Learning Objectives**
Upon completing this lesson, you will be able to:
1. Identify the physical characteristics of the Three-leaf Fan.
2. Explain the function of a DC fan and its role in electronic circuits.
3. Implement the Three-leaf Fan to control airflow using the Raspberry Pi Pico WH.
**Materials Needed**
– Three-leaf Fan
– Breadboard
– Jumper wires
– Raspberry Pi Pico WH
– Motor driver module (e.g., L298N or L293D)
– Power supply (appropriate for the fan, typically 3V or 5V)
– Multimeter (optional)
**Background Information**
The Three-leaf Fan operates as a DC motor with attached fan blades, which creates airflow when the motor spins. These fans are typically used for cooling electronic components or circulating air in small enclosures.
**Fan Characteristics**
The Three-leaf Fan typically has two wires:
– **Red Wire**: Power supply (VCC).
– **Black Wire**: Ground (GND).
**Principles of Operation**
The fan operates by generating airflow when a voltage is applied across its terminals:
– **Fan Speed**: The speed of the fan is proportional to the applied voltage.
– **Direction of Airflow**: The fan blades are designed to move air in a specific direction when the motor rotates.
**Circuit Diagram and Setup**
**Step-by-Step Instructions**
1. **Identify the Fan Wires**:
– Locate the red (VCC) and black (GND) wires on the Three-leaf Fan.
2. **Set Up the Breadboard Circuit**:
– Place the motor driver module on the breadboard.
– Connect the red wire of the fan to one of the output terminals (e.g., OUT1) on the motor driver module.
– Connect the black wire of the fan to the other output terminal (e.g., OUT2) on the motor driver module.
– Connect the input pins (e.g., IN1 and IN2) of the motor driver module to GPIO pins on the Raspberry Pi Pico WH (e.g., GP0 and GP1).
– Connect the motor driver’s VCC pin to an appropriate power supply.
– Connect the motor driver’s GND pin to the ground (GND) pin on the Raspberry Pi Pico WH.
3. **Write the Control Code**:
– Open your MicroPython IDE and write the following code to control the fan:
“`python
from machine import Pin, PWM
from time import sleep
# Initialize GPIO pins for fan control
fan_in1 = Pin(0, Pin.OUT)
fan_in2 = Pin(1, Pin.OUT)
pwm = PWM(Pin(2))
pwm.freq(1000)
def fan_on(speed):
fan_in1.on()
fan_in2.off()
pwm.duty_u16(speed)
def fan_off():
fan_in1.off()
fan_in2.off()
pwm.duty_u16(0)
while True:
fan_on(32768) # Run fan at 50% speed
sleep(5)
fan_off() # Stop fan
sleep(5)
“`
4. **Upload and Test the Code**:
– Connect your Raspberry Pi Pico WH to your computer using a Micro USB cable.
– Upload the code to the Raspberry Pi Pico WH.
– Observe the fan running at 50% speed for 5 seconds, then stopping for 5 seconds. This cycle will repeat continuously.
5. **Optional: Measure Signal Characteristics**:
– Use a multimeter to measure the voltage across the fan terminals to ensure proper operation.
– Verify the current through the fan to ensure it is within safe operating limits.
**Applications and Extensions**
1. **Cooling Systems**:
– Use the Three-leaf Fan in cooling systems to dissipate heat from electronic components such as microcontrollers, sensors, and power supplies.
– Implement temperature control by combining the fan with a temperature sensor.
2. **Air Circulation**:
– Use the fan to create airflow in small enclosures or devices, improving ventilation and preventing overheating.
– Design automated ventilation systems that activate the fan based on environmental conditions.
3. **Interactive Projects**:
– Integrate the fan into interactive projects where airflow control is required, such as wind simulations or automated pet feeders.
– Experiment with different control algorithms to achieve precise airflow control.
**Summary and Review**
This lesson has provided a detailed exploration of the Three-leaf Fan, covering its identification, operational principles, and practical applications in electronic circuits. By understanding and utilizing DC fans, you can create effective cooling and airflow systems for a variety of applications, enhancing the functionality and reliability of your electronic projects.