Micro:Bit LED Ring Tutorial

Tutorial Aim:

To create a rotating color effect on an 8-bit RGB LED strip/module controlled via the KittenBot RobotBit extension. The colors will shift position around the LED ring/strip, cycling smoothly to give a moving light pattern.

Requirements:

This tutorial makes use of the Micro:bit Electronics Learning Package. The parts list is shown below:

Microsoft MakeCode for micro:bit
Micro:bit V2
Micro:bit Robot:bit Expansion Shield V2
8 Bit RGB LED Module
Breakout board
3 Crocodile Clips

Pin Layout:

Micro:Bit Pins:	RGB LED Module Pins:
GND	GND
3.3V	VCC
8	IN

Setup:

Please refer to the diagram below for wiring. Please note that the circuit diagram uses a different Micro:bit shield than the supplied in our package, despite this, the wiring is the same.

Connect the LED ring to pin 8 on the Micro:Bit using the crocodile clips
Open Microsoft Makecode
Plug in the Micro:bit to the computer

Code Walk Through:

Initializing led ring:

To initialize & configure the LED ring we need the robotbit extension by kittenbot. The code for this section will go inside the ‘on start’ block.

For more information about the extension https://makecode.microbit.org/pkg/kittenbot/pxt-robotbit

Adding in the extension: In the extensions tab, search for the robotbit extension by kittenbot
Initializing the led strip: In the Neopixel tab, select “set strip to NeoPixel at P0 with 24 leds as RGB format” & change P0 to P8, and 24 leds to 8 leds
Calibrating the led colours & formation: In the Neopixel tab select “strip show rainbow from 1 to 360”

Displaying & updating the led ring:

Updating the LED ring to rotate colours before displaying the colour formation. To display the colours for a specific duration we can pause the code before it continues to the next iteration . The code for this section will go inside the ‘forever’ block

Displaying the LED colours: In the Neopixel tab select “strip show”
Rotating the pixels: In the Neopixel tab select “rotate pixels by 1”, change the 1 to 10
Pausing the loop for a specified duration: In the Basic block select “pause (ms) 100”

Flashing the code onto the Micro:Bit:

Make sure the Micro:Bit is connected to the computer
On the bottom left corner, click the “Download” button and follow the prompts

Block Code:

Python Code:

strip = neopixel.create(DigitalPin.P8, 8, NeoPixelMode.RGB)
strip.show_rainbow(1, 360)
def on_forever():
    strip.show()
    strip.rotate(10)
    basic.pause(100)
basic.forever(on_forever)

LED Ring Simulation and result:

Downloadable Content:

Please find this tutorial's python & hex file for microsoft makecode on our GitHub.

Credits:

Microsoft
The Micro:bit Community
The STEM Community

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