Hello World with MicroPython

Step 1: Drag and Drop MicroPython on Pico:

Getting MicroPython running on the Raspberry Pi Pico takes a few steps. One way is to download the pre-built release binary from the button below (easiest option).

Download UF2 file

Or you build the MicroPython firmware.uf2 from source if you’d like to customize its low-level aspects (more advanced). This process begins with cloning the MicroPython Github repository and installing CMake and GNU Embedded Toolchain for Arm to assist in building the software.

echo "Terminal commands for installing MicroPython";

echo "Obtaining MicroPython";
cd ~/;
mkdir pico;
cd pico;
git clone -b pico git@github.com:raspberrypi/micropython.git;
    
echo "Obtain additional tools";
sudo apt update;
sudo apt install cmake gcc-arm-non-eabi;

echo "Building MicroPython";
cd micropython;
git submodule update --init --recursive;
make -C mpy-cross;
cd ports/rp2;
make

  

From there, installing the MicroPython software is done by drag and drop programming, in which you drag the firmware.uf2 onto the board as a USB Mass Storage Device. You’ll need to hold down the BOOTSEL button to make it go into USB Mass Storage Device mode.

Step 2: Code through REPL or IDE:

Once the firmware is loaded on board, you’ll be able to connect to the MicroPython REPL (Read Evaluate Print Loop), which is an easy way to test out code and run commands.

Another option is to download the Thonny Python IDE to code through, in which case, once the computer and Pico are connected, you can choose to work with the Raspberry Pi Pico specifically by selecting it from the Interpreter menu within Options (see image below).

Using example code from Raspberry Pi, you can implement code that uses a timer to blink the onboard LED.

##credit of the Raspberry Pi Foundation
from machine import Pin, Timer

led = Pin(25, Pin.OUT)
tim = Timer()
def tick(timer):
global led
led.toggle()


tim.init(freq=2.5, mode=Timer.PERIODIC, callback=tick)
      
  

Since we were working on the top secret Pico before its release, we wanted to communicate with it a bit more cryptically. So, building off the ‘Blink an LED’ code, we built a MicroPython script that outputs “Hello World” in Morse code.

Step 3: Blink "Hello World" in Morse code:

#-------------------------------------------------------------------------------
# Import necessary libraries, connect to on-board LED, set blink rate for LED
#-------------------------------------------------------------------------------

import time
from machine import Pin
led=Pin(25,Pin.OUT)#the LED on the Pico is pin 25
BlinkRate=0.25

#-------------------------------------------------------------------------------
# Functions for the morse code signal durations and the code itself
#-------------------------------------------------------------------------------

def dash():
    led.value(1)
    time.sleep(4*BlinkRate)
    led.value(0)
    time.sleep(BlinkRate)

def dot():
    led.value(1)
    time.sleep(BlinkRate)
    led.value(0)
    time.sleep(BlinkRate)
    
def pause():
    time.sleep(BlinkRate)
    

code = {'A':'.-','B':'-...','C':'-.-.','D':'-..','E':'.','F':'..-.','G':'--.',
    'H':'....','I':'..','J':'.---','K':'-.-','L':'.-..','M':'--','N':'-.',
    'O':'---','P':'.--.','Q':'--.-','R':'.-.','S':'...','T':'-','U':'..-',
    'V':'...-','W':'.--','X':'-..-','Y':'-.--','Z':'--..',
    '0':'-----','1':'.----','2':'..---','3':'...--','4':'....-',
    '5':'.....','6':'-....','7':'--...','8':'---..','9':'----.',
    '.':'.-.-.-',
    ',':'--..--',
    '?':'..--..',
    '/':'--..-.',
    '@':'.--.-.',
    ' ':' / ',
        
}

#-------------------------------------------------------------------------------
# Function that simply returns morse code sentence from uppercase English sentence
#-------------------------------------------------------------------------------

def convertToMorseCode(sentence):
    sentence = sentence.upper() #make it all caps so that the dictionary understands the character
    secretSentence = "" #empty sentence to add to
    for i in sentence: #for each character in the sentence, reference code dictionary and change to morse code character 
        secretSentence += code[i] + " " 
    return secretSentence 

#-------------------------------------------------------------------------------
# main function that blinks LED based on morse code sentence
#-------------------------------------------------------------------------------

while True:
    sentence = "Hello World"
    secretSentence = convertToMorseCode(sentence)
    for i in secretSentence: 
        if i == ".":
            dot()
        elif i == "-":
            dash()
        else:
            pause()