Arduino Serial |Serial.begin()

Arduino Serial |Serial.begin()
Arduino Serial |Serial.begin()

Developers using Arduino hardware must use alternative communication protocols. Serial protocols are popular. Microcontroller-computer communication uses this protocol, which is widespread nowadays. Bytes are used for inter-device communication, reading commands, sending data, etc. The devices send and receive bytes via a single data line, serializing them with the least significant bit (LSB) first.

Your new Arduino board is unpacked. After hearing how useful this little device is for makers and tinkerers, you don’t know where to start. Do not worry! Starting with Serial.begin() to open connection between your computer and the Arduino is the first step to experimenting with your new toy. A simple line of code establishes such connection and allows message exchange. From then, just your imagination limits your creations. Plug your board, start the Arduino program, and start serial connection.

What Is Serial Communication in Arduino?

Serial communication is used with Arduino. This lets the Arduino board and PC exchange data.

The Arduino has USB and serial pins for serial communication. Computer USB ports handle USB connections. Serial pins 0 and 1 on the Arduino Uno connect to other serial devices.

To send serial data using the Arduino IDE’s serial monitor feature, initialize serial communication in your sketch with Serial.begin(). This sets the baud rate, or data transmission speed in bits per second. Most frequent baud rates:

  • 9600 bps
  • 14400 bps
  • 19200 bps
  • 38400 bps
  • 57600 bps
  • 115200 bps

In setup, use:


Send Arduino data to the serial monitor using:

Serial.println(“Hello World!”);

This outputs Hello World! and a new line.

Your sketch can read serial monitor data using:

incoming =;

The variable incoming will receive one byte of data.

Serial connectivity lets you write interactive Arduino programs, communicate sensor data to a computer, and control your Arduino. Endless possibilities!

Understanding the Serial.begin() Function

Serial.begin() initializes serial communication between your Arduino board and a computer or other device. This is needed to print Arduino debug information to the Serial Monitor, communicate with sensors, and upload code.

To use Serial.begin(), pass a baud rate to set communication speed. Most frequent baud rates:

  • 9600
  • 19200
  • 57600
  • 115200

Higher baud rates speed up serial transmission, but both ends must be tuned to the same rate.

For example, to start 9600 baud serial communication:

Serial.begin(9600); Typically used in setup(). Serial can print, read peripherals, and more after Serial.begin().

Serial is often used for:

Sending Serial Monitor debugging data. This lets you get Arduino data while an application is running. For example: Serial.print(“Sensor value: “); Serial.println(sensorValue);
Serially communicating with GPS modules, XBee radios, and serial LCDs. The same baud rate as your Arduino must be set for these devices.
Controlling Arduino with input. From Serial Monitor, you can feed data to the Arduino serial port to trigger sketch operations.
Overall, Serial.begin() configures serial communication between Arduino and other devices. Debugging, peripheral communication, and code uploading need Serial data transmission and reception, which is possible by using this function with a baud rate. Initializing serial connection properly lets you use the Arduino environment and interface with many serial devices.

Choose the Right Serial.begin() Baud Rate

To initialize serial connection in your Arduino sketch, use Serial.begin() with a baud rate. The baud rate controls data transfer in bits per second (bps) between your Arduino and the serial monitor or other serial device.

The right baud rate is crucial for a good connection. Slowness may cause data loss. Too fast and it fails. Common Arduino baud rates:

9600 baud—popular for simple serial transmission. With this slow pace, data is unlikely to be lost.
When sending a lot of data quickly, use 115200 baud. Data can be dropped at this pace, therefore error checking may be needed.
57600 baud—A strong speed-reliability ratio. Fast enough for most needs but little data loss.
The baud rate you choose depends on your application and demands. Tips for finding the best rate:

• Higher baud rates speed data transfer but increase errors. Use the fastest, most dependable speed.

• Simple text can use greater baud rates. Binary or big data may require a lower rate.

• Determine the device’s maximum baud rate and choose a speed within it.

• Serial will get your baud rate as an argument.Start your setup() function using begin():

void setup() { Serials.begin(9600);
• Use the Arduinos IDE Serial Monitor to view data at the same baud rate.

Choosing the right baud rate is essential for quick, error-free serial communication between your Arduino and other devices. Start at a reasonable speed and test to identify your application’s most dependable rate.

Sample Serial.begin() Code

In your Arduino code, use Serials.begin() to initialize serials communication for the Serial monitor. Baud rate is the argument to this function. Data transmission speed is baud rate in bits per second.

For most Arduinos, use 9600 or 115200:

void setup() { Serial.begin(9600);
You can send and receive data from the Serial monitor to your Arduino.

Arduino data is sent using Serial.print() or Serial.println():
The loop function prints “Hello!” followed by a newline using Serial.println and delay(1000).
Print “Hello!” to the Serial monitor, wait 1 second, then repeat.
Read data from the serial port in the loop function on the Arduino:
void loop() { if (Serial.available() > 0) { // Verify data sent char incomingByte =; // Read and process incoming byte } �
If the serial port has received data, this will read the first byte and place it in the incomingByte variable. Take action on that info.
Serial.begin() lets you debug your code and communicate with the Arduino and computer using the Serial monitor. The baud rate can be adjusted to enhance data transfer speed and efficiency for your project or software.


There you have it—a simple Arduino Serials.begin() tutorial. We explained its purpose, popular baud rates, and how to use it in code. Simple stuff! You can now print messages and values over serial to monitor your sketching. To test it, plug in your board, upload a test sketch, and open the serial monitor. Once you have this foundation, you may learn more sophisticated Arduino programming. Have fun experimenting!

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