PySerial Arduino

main.py

import serial

ser = serial.Serial('/dev/ttyACM0', baudrate=9600, timeout=1)
data = ser.readline()
data = str(data, encoding='utf-8')
data = data.strip()

ser.close()
ser.open()

ser.write(b'1')

read.ino

void setup() {
  
  Serial.begin(9600);
  pinMode(LED_BUILTIN, OUTPUT);

}

void loop() {
  if(Serial.available()){
    char Command = Serial.read();
    if(Command == '1')
      digitalWrite(LED_BUILTIN, HIGH);
    else
      digitalWrite(LED_BUILTIN, LOW);
  }
}

write.ino

void setup() {
  
  Serial.begin(9600);

}

void loop() {
  Serial.println("Hello From Arduino");
  delay(1000);
}