Hello Friends, in this blog I will share with you how to control Arduino Digital Output with Serial Monitor. I am using One Arduino Uno, One 330 ohm resistor, One LED, 2 connecting cable, and one small Bread board. LED is connected to pin number 12, with the help of resistor 330 ohm. Below is the sketch: // Code by Deepak Sharma // The code is to control one digital output by serial monitor const int LED = 12; void setup() { // put your setup code here, to run once: Serial.begin(9600); pinMode(LED, OUTPUT); } void loop() { // put your main code here, to run repeatedly: if (Serial.available()) { String input = Serial.readStringUntil('\n'); input.trim(); if (input.equalsIgnoreCase("ON")) { digitalWrite(LED, HIGH); Serial.println("LED ON"); } else if (input.equalsIgnoreCase("OFF")) { digitalWrite(LED, LOW); ...