Introduction to Python and Microcontrollers

LED Pixel

Control a Freenove 8 RGB LED Module (WS2812 “NeoPixel” LEDs) using only a single GPIO pin, cycling each of the 8 LEDs through red, green, blue, white, and off.

New Concepts

• Addressable RGB LEDs (WS2812 / NeoPixel)
• The neopixel module

Freenove 8 RGB LED Module

The module packs 8 WS2812 LEDs, each with its own red, green, and blue element (256 brightness levels per color — 16,777,216 possible colors per LED). Unlike a standard RGB LED, each WS2812 only needs a single data pin: it reads its own color data from the signal, then passes the rest down the line to the next LED. This lets multiple modules be chained by connecting one module’s OUT to the next module’s IN, controlling 8, 16, 24… LEDs from a single GPIO pin.

neopixel module

This module helps you control the Freenove 8 RGB LED Module. See reference/Class_neopixel.md for documentation on this module.

Component List

Circuit

Wiring Diagram

Disconnect all power before building the circuit. Reconnect once verified.

Connections:

• Module IN side: S → GPIO48, V → 5V, G → GND

Schematic Diagram

Code

File: 02_input_and_output/code/Neopixel.py

from machine import Pin
import neopixel
import time
pin = Pin(48, Pin.OUT)
np = neopixel.NeoPixel(pin, 8)

#brightness :0-255
brightness=10                                
colors=[[brightness,0,0],                    #red
        [0,brightness,0],                    #green
        [0,0,brightness],                    #blue
        [brightness,brightness,brightness],  #white
        [0,0,0]]                             #close
    
while True:
    for i in range(0,5):
        for j in range(0,8):
            np[j]=colors[i]
            np.write()
            time.sleep_ms(50)
        time.sleep_ms(500)
    time.sleep_ms(500)

How to Run

Online

1. Open Thonny → 02_input_and_output/code/.
2. Double-click Neopixel.py.
3. Click Run current script — all 8 LEDs cycle through red, green, blue, white, then off.

Code Explanation

Set up the module

pin = Pin(48, Pin.OUT)
np = neopixel.NeoPixel(pin, 8)

Associates GPIO48 with a NeoPixel object controlling 8 LEDs.

Define brightness and colors

brightness=10
colors=[[brightness,0,0],
        [0,brightness,0],
        [0,0,brightness],
        [brightness,brightness,brightness],
        [0,0,0]]

Each entry in colors is an [R, G, B] triple. brightness (0–255) scales how bright each color appears.

Apply a color to every LED

for i in range(0,5):
    for j in range(0,8):
        np[j]=colors[i]
        np.write()
        time.sleep_ms(50)
    time.sleep_ms(500)

The outer loop steps through the 5 colors. The inner loop assigns that color to each of the 8 LEDs in the np array — but nothing happens on the physical module until np.write() sends the array data down the line.

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Key Concepts

• Addressable LEDs: each WS2812 LED stores and forwards its own color data, so a whole chain can be driven from one GPIO pin
• np[j] = [r,g,b]: stages a color for LED j without sending it yet
• np.write(): sends the staged color data to the physical LEDs

See Class neopixel for the full API reference.

Further Exploration

• Change brightness to make the cycle dimmer or brighter.
• Add more colors to the colors list (e.g. purple, orange).

Back to Module

Adapted from Python_Tutorial.pdf Project 6.1

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