arduino/04_communication/physical_pixel/main.py

Turns the on-board LED on when it receives "H" and off when it receives "L" from the computer. Type the letters in the REPL terminal while the script runs: in PyCharm, run it with Execute File in REPL and type in the REPL tab. mpremote run doesn't pass typed letters on, so copy it to the board as main.py, press RESET, then type in mpremote repl. sys.stdin.read(1) waits for the next character, so loop() pauses until one arrives.

# Turns the on-board LED on when it receives "H" and off when it receives "L"
# from the computer. Type the letters in the REPL terminal while the script
# runs: in PyCharm, run it with Execute File in REPL and type in the REPL tab.
# mpremote run doesn't pass typed letters on, so copy it to the board as
# main.py, press RESET, then type in mpremote repl.
#
# sys.stdin.read(1) waits for the next character, so loop() pauses until one
# arrives.
 
import sys  # sys.stdin: characters typed in the terminal
 
from arduino import *  # the Arduino-style functions: pinMode(), digitalWrite(), delay(), ...
 
 
def setup():
    pinMode(LED_BUILTIN, OUTPUT)  # the LED's pin as an output
    digitalWrite(LED_BUILTIN, LOW)  # start with the LED off
    print("Type H to turn the LED on, L to turn it off.")
 
 
def loop():
    char = sys.stdin.read(1)  # wait for one character from the terminal
    if char == "H":
        digitalWrite(LED_BUILTIN, HIGH)
    elif char == "L":
        digitalWrite(LED_BUILTIN, LOW)
    # Any other character is ignored.
 
 
# Do not edit below this line: it runs setup() once, then loop() over and over.
def main():
    setup()  # runs once, at the start
    while True:  # repeats until stopped: Interrupt in PyCharm, or mpremote soft-reset
        loop()
 
 
# True when this file is run, but not when another file imports it.
if __name__ == "__main__":
    main()