Arduino Serial Communication: A Guide

Serial communication is an essential feature in Arduino for connecting with other devices. It allows you to “talk” to a computer, visualize data from the Arduino, debug projects, and communicate with other devices. In this guide, we will explore how to effectively use serial communication in Arduino.

Arduino comes equipped with the built-in Serial library, eliminating the need to import any additional libraries to use it. The USB connection established between the computer and the Arduino for programming purposes also enables serial communication, enabling you to send and receive messages through the Arduino IDE effortlessly.

To send data through the serial in Arduino, you need to initialize the serial communication by setting the data rate (baud rate) in the setup() function of your Arduino program. The default baud rate is usually set to 9600. Here’s an example of how to set the baud rate:

Serial.begin(9600);

Once the serial communication is initialized, you can make use of the various functions available in the Serial library. For instance, the Serial.print() function allows you to send data to the serial interface. Here’s an example:

Serial.print("Hello!");

To demonstrate this, you can compile and upload the following program to your Arduino:

void setup() {
 Serial.begin(9600);
 Serial.print("Hello!");
}

void loop() {
}

After uploading the program, click the “Serial Monitor” button located at the top-right corner of the Arduino IDE. It will open the serial interface monitor on your computer. Ensure that the baud rate in the monitor matches the one set in your program. You should see the “Hello!” string being printed in the monitor.

Apart from Serial.print(), there is another useful function called Serial.println(). It writes a message and adds a line terminator (\n), making each message appear on a separate line.

You can also send messages from the serial interface monitor back to the Arduino. To read the input, you can use the Serial.read() function. Characters are encoded using ASCII. Here’s an example:

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

void loop() {
 if (Serial.available() > 0) {
 Serial.print(Serial.read());
 }
}

When you run this program and send characters (e.g., “test”) from the serial interface monitor, the ASCII decimal value of each character will be printed back. It’s worth using Serial.println() instead to ensure each number is printed on a separate line.

To print the characters themselves instead of their ASCII encoding, you can utilize the Serial.write() function:

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

void loop() {
 if (Serial.available() > 0) {
 Serial.write(Serial.read());
 }
}

In this case, the characters you send from the serial interface monitor will be directly printed as their respective characters.

Remember that on Arduino boards, there are specific tx and rx pins dedicated to serial communication. For example, on Arduino Uno, they are pins 0 and 1, while on an Arduino MKR 1010, they are pins 13 and 14. It’s essential not to use these pins for I/O when utilizing serial communication via USB to avoid data interferences.

In summary, Arduino serial communication is a powerful tool for interacting with other devices and computers. By utilizing the Serial library’s functions such as Serial.print(), Serial.println(), Serial.read(), and Serial.write(), you can easily exchange data and debug your Arduino projects.

Tags: Arduino, Serial Communication, USB, Baud Rate, ASCII Encoding, Serial Interface, Communication Functions