RGB LED Cycle Using Raspberry Pi Pico (MicroPython)

 

🔴🟢🔵 Button-Controlled RGB LED Cycle Using Raspberry Pi Pico (MicroPython)

Objective

• To demonstrate how to use a push button to cycle through three different LEDs (Red, Green, and Blue) connected to a Raspberry Pi Pico.

• To learn input reading, edge detection, and RGB control in MicroPython.

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Components Required

S.N.	Component	Quantity
1	Raspberry Pi Pico	1
2	Red LED	1
3	Green LED	1
4	Blue LED	1
5	Push Button	1
6	220Ω Resistors	3 (optional)
7	Breadboard + Jumper Wires	As needed
8	Micro USB Cable	1

Circuit Description

• Red LED → GPIO 2

• Green LED → GPIO 1

• Blue LED → GPIO 0

• All cathodes of the LEDs go to GND through 220Ω resistors.

• Push Button → GPIO 15, with internal pull-down resistor enabled using Pin.PULL_DOWN.

:::::circuit diagram:::::

                                                               

::::Video Link::::

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Working Principle

The MicroPython script continuously monitors the button state. When a button press (rising edge) is detected:

1. A counter is incremented.

2. Based on the value of the counter (1 to 3), it lights up one of the LEDs:

   • 1 = Red

   • 2 = Green

   • 3 = Blue

3. After 3, the counter resets to 1, creating a looped LED cycle.

4. A debounce delay is used to avoid repeated triggering from mechanical button noise.

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Code: MicroPython

python
from machine import Pin
from time import sleep

# Define input button and output LEDs
button = Pin(15, Pin.IN, Pin.PULL_DOWN)
led0 = Pin(0, Pin.OUT)  # Blue
led1 = Pin(1, Pin.OUT)  # Green
led2 = Pin(2, Pin.OUT)  # Red

count = 0
last_button_state = 0

print("Welcome to Kailash Raspberry Pi Pico Series")

# Function to turn off all LEDs
def turn_off_leds():
    led0.off()
    led1.off()
    led2.off()

while True:
    current_state = button.value()

    # Detect rising edge of button press
    if current_state == 1 and last_button_state == 0:
        count += 1
        if count > 3:
            count = 1  # reset to 1 to cycle again

        turn_off_leds()  # turn off all LEDs before lighting the next

        if count == 1:
            print("Red")
            led2.on()
        elif count == 2:
            print("Green")
            led1.on()
        elif count == 3:
            print("Blue")
            led0.on()

        sleep(0.3)  # debounce delay

    last_button_state = current_state
    sleep(0.01)  # short delay to reduce CPU usage

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Sample Output

mathematical
Welcome to Kailash Raspberry Pi Pico Series
Red
Green
Blue
Red
...

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Applications

• RGB LED control

• Simple color-coded feedback system

• Learn edge detection and state transitions in embedded systems

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Advantages

• Teaches button debouncing and state machine logic

• Scalable to add more LEDs or modes

• Beginner-friendly GPIO and logic structure

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Limitations

• No PWM (only full ON/OFF LEDs)

• No long-press detection

• Button bounces handled by fixed delay (not interrupt-based)

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References

• assistance by ChatGpt

• Compiler is thonny application

• Practical implementation tested and verified by Kailash

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Conclusion

This simple project helps you grasp GPIO input-output interactions and logic flow on Raspberry Pi Pico. Use of RGB led .

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