Getting started with Maker Nano RP2040 using CircuitPython: Blinky, RGB LED, and Piezo Buzzer

CNXSoft: This getting started guide was initially posted in Thai language by Suthinee Kerdkaew, and I’ve just translated her work into English with some minor edits.

As discussed in an earlier article, Maker Nano RP2040 is a board following the Arduino Nano form factor, but with a more powerful Raspberry Pi RP2040 microcontroller. The board also comes with plenty of LEDs, as well as two RGB LEDs, and a piezo buzzer for audio output.

Mr. Jean-Luc Aufranc has just given me a Maker Nano RP2040 board received from Cytron for review. I’ve never used a board before, so it’s my first experience, and in this article, I’ll try to program Maker Nano RP2040 with CircuitPython with three demos: a blinky sample, changing the color of the RGB LEDs, and playing a melody through the piezo buzzer. Let’s see if I can do it.

Let’s get started. I first downloaded the CircuitPython firmware from the official website. Simply select the language, and click on “DOWNLOAD.UF2 NOW”

After downloading the file, I connected the board to my Ubuntu laptop with a Micro USB to USB cable. It will automatically mount a drive named “CIRCUITPY”. Oh! That means the Maker Nano RP2040 board comes pre-installed with CircuitPython, so we can use the board out of the box! But if you wanted to install the latest version of the firmware, you could do so using the same firmware update method as for Raspberry Pi Pico.

We can double-click on code.py to see the sample program pre-installed on the board. There’s a lot of code and it would be difficult for a beginner like me to understand.

CircuitPython “Blinky” sample

So I want to write a program that’s easy: the typical “blinky” program that blinks an LED regularly using CircuitPython. The code looks as follows:

import board
import digitalio
import time

# Set pin 0 as digital output
led = digitalio.DigitalInOut(board.GP0)
led.direction = digitalio.Direction.OUTPUT

# -------------------------------------------------
# FOREVER LOOP - Blink the LED every second (0.5s on, 0.5s off)
# -------------------------------------------------
while True:
    
    led.value = True
    time.sleep(0.5)
    led.value = False
    time.sleep(0.5)

import board

import digitalio

import time

# Set pin 0 as digital output

led = digitalio.DigitalInOut(board.GP0)

led.direction = digitalio.Direction.OUTPUT

# -------------------------------------------------

# FOREVER LOOP - Blink the LED every second (0.5s on, 0.5s off)

# -------------------------------------------------

while True:

led.value = True

time.sleep(0.5)

led.value = False

time.sleep(0.5)

We can see the blue LED connected to GPIO 0 turn on and off every 500 ms (1-second cycle) as shown in the video below.

Using the RGB LEDs on Maker Nano RP2040

In the next step, we will write a program in CircuitPython that changed the color of the two RGB LEDs upon pressing the button connected to GPIO 20. The first press will switch to red, the second to green, and the third to blue. Let’s start by double-clicking on code.py to change the code to:

import board
import digitalio
import neopixel
import simpleio
import time
import pwmio

# Initialize Neopixel RGB LEDs
pixels = neopixel.NeoPixel(board.GP11, 2)
pixels.fill(0)
pixels.brightness = 0.1

# Initialize the button 
btn1 = digitalio.DigitalInOut(board.GP20)
btn1.direction = digitalio.Direction.INPUT
btn1.pull = digitalio.Pull.UP

color = 0
state = 0

# -------------------------------------------------
# FOREVER LOOP: Check buttons & animate RGB LEDs
# -------------------------------------------------
while True:
    
    # Check button 1 (GP20)
    if not btn1.value:  # button 1 pressed        
    # Change RGB LED color 
    	if state == 0:
            color = 0xFF0000   # RED
            state += 1
    	elif state == 1:
            color = 0x00FF00   # GREEN
            state += 1
        else:
            color = 0x0000FF   # BLUE 
            state = 0
    
    pixels.fill(color)  # fill the color on both RGB LEDs
    
    # Sleep to debounce button (200ms delay to make sure multiple presses are not wrongly detected by the loop)
    time.sleep(0.2)

import board

import digitalio

import neopixel

import simpleio

import time

import pwmio

# Initialize Neopixel RGB LEDs

pixels = neopixel.NeoPixel(board.GP11, 2)

pixels.fill(0)

pixels.brightness = 0.1

# Initialize the button

btn1 = digitalio.DigitalInOut(board.GP20)

btn1.direction = digitalio.Direction.INPUT

btn1.pull = digitalio.Pull.UP

color = 0

state = 0

# -------------------------------------------------

# FOREVER LOOP: Check buttons & animate RGB LEDs

# -------------------------------------------------

while True:

# Check button 1 (GP20)

if not btn1.value: # button 1 pressed

# Change RGB LED color

if state == 0:

color = 0xFF0000 # RED

state += 1

elif state == 1:

color = 0x00FF00 # GREEN

state += 1

else:

color = 0x0000FF # BLUE

state = 0

pixels.fill(color) # fill the color on both RGB LEDs

# Sleep to debounce button (200ms delay to make sure multiple presses are not wrongly detected by the loop)

time.sleep(0.2)

We can now change the colors to red, green, and blue following the steps in the video below.

Playing a melody through the piezo buzzer

We’ll now play the melody “do re mi fa sol la si/ti” and in reverse using the piezo buzzer. For this, we’ll need to fill the frequencies in Hz for each music note in an array. Here’s our little program:

import board
import digitalio
import neopixel
import simpleio
import time
import pwmio

# Initialize Neopixel RGB LEDs
pixels = neopixel.NeoPixel(board.GP11, 2)
pixels.fill(0)
pixels.brightness = 0.2

# Melody arrays: NOTE with the frequencies in HZ, and DURATION in seconds
MELODY_NOTE = [262, 294, 330, 349, 392, 440, 494] 
MELODY_DURATION = [0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5] 

# Define pin connected to piezo 
PIEZO_PIN = board.GP22
 
for i in range(len(MELODY_NOTE)):
	# Play melody tones
	simpleio.tone(PIEZO_PIN, MELODY_NOTE[i], duration=MELODY_DURATION[i])
	color = 0x7FFF * MELODY_NOTE[i]   # Frequency based color
	pixels.fill(color)  # fill the color on both RGB LEDs

for x in range(len(MELODY_NOTE)-1, -1, -1): 
        # Play melody tones in reverse order
	simpleio.tone(PIEZO_PIN, MELODY_NOTE[x], duration=MELODY_DURATION[x])
	color = 0x1FFF * MELODY_NOTE[x]   # Frequency based color
	pixels.fill(color)  # fill the color on both RGB LEDs
    
# -------------------------------------------------
# FOREVER LOOP 
# -------------------------------------------------
while True:
     time.sleep(1)

import board

import digitalio

import neopixel

import simpleio

import time

import pwmio

# Initialize Neopixel RGB LEDs

pixels = neopixel.NeoPixel(board.GP11, 2)

pixels.fill(0)

pixels.brightness = 0.2

# Melody arrays: NOTE with the frequencies in HZ, and DURATION in seconds

MELODY_NOTE = [262, 294, 330, 349, 392, 440, 494]

MELODY_DURATION = [0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5]

# Define pin connected to piezo

PIEZO_PIN = board.GP22

for i in range(len(MELODY_NOTE)):

# Play melody tones

simpleio.tone(PIEZO_PIN, MELODY_NOTE[i], duration=MELODY_DURATION[i])

color = 0x7FFF * MELODY_NOTE[i] # Frequency based color

pixels.fill(color) # fill the color on both RGB LEDs

for x in range(len(MELODY_NOTE)-1, -1, -1):

# Play melody tones in reverse order

simpleio.tone(PIEZO_PIN, MELODY_NOTE[x], duration=MELODY_DURATION[x])

color = 0x1FFF * MELODY_NOTE[x] # Frequency based color

pixels.fill(color) # fill the color on both RGB LEDs

# -------------------------------------------------

# FOREVER LOOP

# -------------------------------------------------

while True:

time.sleep(1)

We can hear the melody in the video below.

I could eventually program the board successfully! Finally, I must thank Jean-Luc Aufranc for his guidance during this review.

Jean-Luc Aufranc (CNXSoft)

Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.