Note

Hello, welcome to the SunFounder Raspberry Pi & Arduino & ESP32 Enthusiasts Community on Facebook! Dive deeper into Raspberry Pi, Arduino, and ESP32 with fellow enthusiasts.

Why Join?

Expert Support: Solve post-sale issues and technical challenges with help from our community and team.
Learn & Share: Exchange tips and tutorials to enhance your skills.
Exclusive Previews: Get early access to new product announcements and sneak peeks.
Special Discounts: Enjoy exclusive discounts on our newest products.
Festive Promotions and Giveaways: Take part in giveaways and holiday promotions.

👉 Ready to explore and create with us? Click [here] and join today!

1.2 RGB LED

Introduction

In this project, we will explore how to control an RGB LED to display various colors by using a Raspberry Pi and GPIO programming. RGB LEDs are versatile components that can emit a spectrum of colors by mixing red, green, and blue light at different intensities.

What You’ll Need

To complete this project, you will need the following components:

COMPONENT	PURCHASE LINK
Breadboard	BUY
Jumper Wires	BUY
Resistor	BUY
RGB LED	BUY
Fusion HAT+	-
Raspberry Pi	-

Circuit Diagram

After connecting the R, G, and B pins of the RGB LED to current-limiting resistors, connect these resistors to PWM0, PWM1, and PWM2, respectively. The longest pin of the LED (GND) is connected to the GND pin of the Raspberry Pi. Different PWM values for the three pins produce various colors.

Wiring Diagram

Follow the steps below to build the circuit:

Place the RGB LED on the breadboard.
Connect the red, green, and blue pins of the LED to P0, P1, and P2 through resistors.
Connect the longest pin (GND) of the LED to the GND of the Raspberry Pi.

Running the Example

All example code used in this tutorial is available in the ai-lab-kit directory. Follow these steps to run the example:

cd ~/ai-lab-kit/python/
sudo python3 1.2_RGBLED.py

After running the program, the RGB LED lights up red, then green, then purple, each for 1 second, and finally turns off. Pressing Ctrl + C will also turn the LED off.

Code

The following Python code cycles through various colors on the RGB LED by setting different PWM values for the red, green, and blue components:

#!/usr/bin/env python3
from fusion_hat.modules import RGB_LED
from fusion_hat.pwm import PWM
from time import sleep

# Initialize an RGB LED. Connect the red component to P0, green to P1, and blue to P2.
rgb_led = RGB_LED(PWM(0), PWM(1), PWM(2), common=RGB_LED.CATHODE)

try:
   # Set the RGB LED to red.
   rgb_led.color((255, 0, 0))
   sleep(1)

   # Set the RGB LED to green.
   rgb_led.color("#00FF22")
   sleep(1)

   # Set the RGB LED to purple.
   rgb_led.color(0xFF00FF)
   sleep(1)

   # Set the RGB LED to black.
   rgb_led.color(0x000000)

except KeyboardInterrupt:
   # Handle a KeyboardInterrupt (Ctrl+C) to exit.
   rgb_led.color(0x000000)
   pass

This script demonstrates how to control an RGB LED using the Fusion Hat library. It initializes the RGB LED with specific PWM pins and sets different colors sequentially.

Understanding the Code

Run the script on a compatible device with a connected RGB LED. The LED will cycle through red, green, and purple before turning off.

Importing Dependencies
```
from fusion_hat.modules import RGB_LED
from fusion_hat.pwm import PWM
from time import sleep
```
The required modules are imported. RGB_LED and PWM from the fusion_hat library manage the RGB LED, and sleep is used for timing.
Initializing the RGB LED
```
rgb_led = RGB_LED(PWM(0), PWM(1), PWM(2), common=RGB_LED.CATHODE)
```
The RGB LED is initialized with its red, green, and blue components connected to PWM pins P0, P1, and P2, respectively. The LED uses a common cathode configuration.
Setting Colors Sequentially
```
rgb_led.color((255, 0, 0))  # Red
sleep(1)

rgb_led.color("#00FF22")  # Green
sleep(1)

rgb_led.color(0xFF00FF)  # Purple
sleep(1)
```
The script sets the RGB LED to different colors using different formats:
- (255, 0, 0): Tuple representing red in RGB.
- "#00FF22": Hexadecimal string representing a greenish color.
- 0xFF00FF: Hexadecimal integer for purple.
Turning Off the LED
```
rgb_led.color(0x000000)
```
The script sets the LED color to black (0x000000), effectively turning it off.
Handling Interrupts
```
except KeyboardInterrupt:
   rgb_led.color(0x000000)
   pass
```
If the user interrupts the script using Ctrl+C, the exception is caught, and the LED is turned off before exiting.

Troubleshooting

LED Does Not Light Up
- Cause: Incorrect wiring or GPIO pin mismatch.
- Solution: Verify that the red, green, and blue pins of the RGB LED are connected to the correct pins and that the LED’s common cathode or anode is properly connected.
Flickering or Unstable Colors
- Cause: Unstable power supply or improper resistor usage.
- Solution: Use appropriate resistors and ensure a stable power source.
Incorrect GPIO Setup
- Cause: Fusion_hat library is not installed.
- Solution: See Install fusion-hat module.

Extendable Ideas

Custom Color Sequences

Add more colors to the COLORS list, including dimmer variations, such as (125, 50, 200) for a softer tone.

User-Defined Colors

Allow the user to input custom RGB values:

while True:
    user_color = input("Enter RGB values (e.g., 125,0,0): ")
    r, g, b = map(int, user_color.split(","))
    rgb_led.color = (r, g, b)

Randomized Colors

Generate random colors to create a dynamic and unpredictable light display:

from random import randint
while True:
   rgb_led.color = (randint(1,255) , randint(1,255) , randint(1,255) )
   sleep(1)

Conclusion

By following this guide, you have successfully learned how to control an RGB LED using a Raspberry Pi and Python. This project demonstrates the basics of PWM and color mixing, which can be expanded into more advanced lighting effects or used as a foundation for interactive projects.