Serial Communication with PC Experiment

Introduction

Serial communication is a fundamental way to exchange data between a microcontroller and a PC. This experiment demonstrates how to use Arduino to send and receive data via the serial port, enabling interaction with the PC through the Serial Monitor or a custom interface.

Components Needed

• Arduino (e.g., Uno, Nano)
• USB cable for programming and communication
• Breadboard and jumper wires (optional, for additional peripherals)

Circuit Setup

No additional hardware is needed for basic serial communication. Connect your Arduino to your PC using a USB cable.

If testing with additional hardware (e.g., LEDs or buttons), follow these steps:

1. Connect an LED with a 220Ω resistor to a digital pin (e.g., pin 13).
2. Connect a push button to a digital input pin with a pull-down resistor (e.g., pin 2).

Code for Serial Communication

Upload the following code to your Arduino to test serial communication:

// Basic Serial Communication Example

void setup() {
    Serial.begin(9600); // Start serial communication at 9600 baud
    pinMode(13, OUTPUT); // Optional: LED pin
    pinMode(2, INPUT_PULLUP); // Optional: Button pin
}

void loop() {
    // Check if data is available from the PC
    if (Serial.available() > 0) {
        char command = Serial.read(); // Read the incoming data
        if (command == 'H') {
            digitalWrite(13, HIGH); // Turn on LED
            Serial.println("LED ON");
        } else if (command == 'L') {
            digitalWrite(13, LOW); // Turn off LED
            Serial.println("LED OFF");
        } else {
            Serial.println("Unknown command. Use 'H' or 'L'.");
        }
    }

    // Optional: Send button state to PC
    if (digitalRead(2) == LOW) { // Button pressed
        Serial.println("Button Pressed");
        delay(200); // Debounce delay
    }
}
            

Explanation

• Serial.begin(9600): Initializes serial communication at a baud rate of 9600.
• Serial.read(): Reads a character from the serial input buffer.
• Serial.println(): Sends a message to the Serial Monitor for debugging or interaction.
• In the loop:
  • Commands 'H' and 'L' control an LED connected to pin 13.
  • The button state is continuously checked and sent to the PC when pressed.

Using the Serial Monitor

1. Open the Arduino IDE Serial Monitor (or any serial terminal).
2. Set the baud rate to 9600.
3. Enter 'H' to turn on the LED or 'L' to turn it off.
4. Observe responses from the Arduino in the Serial Monitor.

Troubleshooting

• If no response is received, verify the USB connection and correct COM port in the Arduino IDE.
• Ensure the baud rate in the Serial Monitor matches the one in the code (9600).
• Test with a basic serial echo program to verify communication.