In this manipulation we will see how to Drive a Digital Output hooked into the Arduino via the pin #13, and that by giving it a real-time command from a Tkinter ON/OFF Botton.

Hardware

• Arduino Uno board or any other compatible version.
• LED connected to the pin #13 (or simply the built-in LED).
• Serial medium: USB cable connected to a serial monitor or Pin#0_(RX), Pin#1_(TX) for Arduino Uno.

Th Code

• Arduino code:

const int ledPin = 13; // the pin that the LED is attached to
int incomingByte;      // a variable to read incoming serial data into
 
void setup() {
  // initialize serial communication:
  Serial.begin(9600);
  // initialize the LED pin as an output:
  pinMode(ledPin, OUTPUT);
}
 
void loop() {
  // see if there's incoming serial data:
  if (Serial.available() > 0) {
    // read the oldest byte in the serial buffer:
    incomingByte = Serial.read();
    // if it's a capital H (ASCII 72), turn on the LED:
    if (incomingByte == 'H') {
      digitalWrite(ledPin, HIGH);
    }
    // if it's an L (ASCII 76) turn off the LED:
    if (incomingByte == 'L') {
      digitalWrite(ledPin, LOW);
    }
  }
}

• Python Code

import serial
import time
import tkinter
 
 
def quit_button():
    global tkTop
    ser.write(bytes('L', 'UTF-8'))
    tkTop.destroy()
 
def on_button():
        varLabel.set("LED ON ")
        ser.write(bytes('H', 'UTF-8'))
 
def off_button():
        varLabel.set("LED OFF")
        ser.write(bytes('L', 'UTF-8'))
 
#change the COM port below
ser = serial.Serial('COM7', 9600)
print("Reset Arduino")
time.sleep(2)
ser.write(bytes('L', 'UTF-8'))
 
tkTop = tkinter.Tk()
tkTop.geometry('300x300') #300 x 300 window
tkTop.title("LED control") #name in title bar
 
#label to display the status
varLabel = tkinter.IntVar()
tkLabel = tkinter.Label(textvariable=varLabel, )
varLabel.set("LED STATUS")
tkLabel.pack()
 
#button1 - ON
button1 = tkinter.IntVar()
button1state = tkinter.Button(tkTop,
    text="ON",
    command=on_button,
    height = 4,
    width = 8,
)
button1state.pack(side='top', ipadx=10, padx=10, pady=15)
 
#button2 - OFF
button2 = tkinter.IntVar()
button2state = tkinter.Button(tkTop,
    text="OFF",
	command=off_button,
    height = 4,
    width = 8,
)
button2state.pack(side='top', ipadx=10, padx=10, pady=15)
 
#Quit button
tkButtonQuit = tkinter.Button(
    tkTop,
    text="Quit",
    command=quit_button,
    height = 4,
    width = 8,
)
 
tkButtonQuit.pack(side='top', ipadx=10, padx=10, pady=15)
tkinter.mainloop()

The outcoming result