Raspberry Pi 4 Official Case Fan

Raspberry Pi 4 Official Case Fan Documentation

Overview
The Raspberry Pi 4 Official Case Fan is a high-quality, compact fan designed specifically for the Raspberry Pi 4 case. It provides efficient cooling for the Raspberry Pi 4, ensuring stable performance and prolonging the lifespan of the board.

Technical Specifications

Dimensions: 30mm x 30mm x 7mm
 Power Consumption: 5V, 0.2A
 Noise Level: 20dBA
 Airflow: 3.4 CFM
 Connector: 2-pin JST-PH (compatible with Raspberry Pi 4 GPIO)

Programming and Control

The Raspberry Pi 4 Official Case Fan can be controlled and monitored using the Raspberry Pi's GPIO pins. Here are some code examples to demonstrate how to use the fan in different contexts:

Example 1: Basic Fan Control using Python

In this example, we will use Python to control the fan's ON/OFF state.

Code:
```python
import RPi.GPIO as GPIO
import time

# Set up GPIO library
GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)

# Define fan pin
fan_pin = 17

# Set fan pin as output
GPIO.setup(fan_pin, GPIO.OUT)

try:
    while True:
        # Turn fan ON
        GPIO.output(fan_pin, GPIO.HIGH)
        print("Fan is ON")
        time.sleep(5)

# Turn fan OFF
        GPIO.output(fan_pin, GPIO.LOW)
        print("Fan is OFF")
        time.sleep(5)

except KeyboardInterrupt:
    # Clean up GPIO
    GPIO.cleanup()
```
Example 2: Temperature-based Fan Control using Python

In this example, we will use Python to control the fan based on the Raspberry Pi's temperature.

Code:
```python
import RPi.GPIO as GPIO
import time
import os

# Set up GPIO library
GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)

# Define fan pin
fan_pin = 17

# Set fan pin as output
GPIO.setup(fan_pin, GPIO.OUT)

try:
    while True:
        # Get temperature from Raspberry Pi
        temp = int(os.popen("vcgencmd measure_temp").read()[5:-3])

# Turn fan ON if temperature exceeds 60C
        if temp > 60:
            GPIO.output(fan_pin, GPIO.HIGH)
            print("Fan is ON (Temperature: {}C)".format(temp))
        else:
            GPIO.output(fan_pin, GPIO.LOW)
            print("Fan is OFF (Temperature: {}C)".format(temp))

time.sleep(5)

except KeyboardInterrupt:
    # Clean up GPIO
    GPIO.cleanup()
```
Example 3: Fan Control using systemd Service (Raspbian OS)

In this example, we will create a systemd service to control the fan based on the Raspberry Pi's temperature.

Code:
Create a file `/etc/systemd/system/fan_control.service` with the following contents:
```bash
[Unit]
Description=Fan Control Service

[Service]
User=root
ExecStart=/usr/bin/python /home/pi/fan_control.py
Restart=always

[Install]
WantedBy=multi-user.target
```
Create a file `/home/pi/fan_control.py` with the following contents:
```python
import os
import time

while True:
    # Get temperature from Raspberry Pi
    temp = int(os.popen("vcgencmd measure_temp").read()[5:-3])

# Turn fan ON if temperature exceeds 60C
    if temp > 60:
        os.system("gpio -g write 17 1")
        print("Fan is ON (Temperature: {}C)".format(temp))
    else:
        os.system("gpio -g write 17 0")
        print("Fan is OFF (Temperature: {}C)".format(temp))

time.sleep(5)
```
Enable and start the service:
```bash
sudo systemctl enable fan_control.service
sudo systemctl start fan_control.service
```
These examples demonstrate how to control the Raspberry Pi 4 Official Case Fan using Python and systemd services. You can modify the code to suit your specific requirements and applications.