What is Software Serial Arduino?

Software Serial Arduino is a library that enables you to create additional serial ports on the Arduino board using software instead of hardware. With Software Serial, you can communicate with multiple devices simultaneously, even if your Arduino board has only one hardware serial port.

The Software Serial library works by using the Arduino’s digital pins to emulate a serial port. It uses interrupts to receive data and a timer to transmit data, which allows it to function independently of the main program loop. This means that you can use Software Serial to communicate with devices without blocking the execution of your main program.

How to Use Software Serial Arduino

To use Software Serial Arduino, you first need to include the library in your sketch. You can do this by adding the following line at the beginning of your code:

#include <SoftwareSerial.h>

Next, you need to create an instance of the Software Serial object, specifying the digital pins you want to use for transmitting (TX) and receiving (RX) data. For example, if you want to use digital pins 2 and 3 for your Software Serial communication, you would create the object like this:

SoftwareSerial mySerial(2, 3); // RX, TX

Once you have created the Software Serial object, you can use it just like you would use the hardware serial port. You can initialize the serial communication using the begin() function, specifying the baud rate you want to use:

mySerial.begin(9600);

To send data over the Software Serial port, you can use the print() or println() functions, just like you would with the hardware serial port:

mySerial.println("Hello, world!");

To receive data from the Software Serial port, you can use the available() and read() functions. The available() function returns the number of bytes available to read, while the read() function reads a single byte from the buffer:

if (mySerial.available()) {
  char incomingByte = mySerial.read();
  // Do something with the incoming byte
}

Advantages and Disadvantages of Software Serial Arduino

Software Serial Arduino has both advantages and disadvantages compared to using the hardware serial port. Let’s take a look at some of them:

Advantages

• Allows you to create additional serial ports on the Arduino board
• Enables you to communicate with multiple devices simultaneously
• Works independently of the main program loop, so it doesn’t block execution
• Easy to use and implement in your code

Disadvantages

• Slower than hardware serial communication (limited to 115200 baud)
• Can be unreliable at high baud rates or with long cable lengths
• Uses more processing power than hardware serial communication
• Can interfere with other libraries that use interrupts or timers

Example Projects Using Software Serial Arduino

Now that you know the basics of Software Serial Arduino, let’s explore some example projects that demonstrate its capabilities.

Project 1: Connecting a GPS Module

In this project, we will connect a GPS module to the Arduino board using Software Serial communication. The GPS module will send location data to the Arduino, which will then display it on the serial monitor.

Hardware Required:
– Arduino UNO board
– GPS module (e.g., NEO-6M)
– Jumper wires

Connections:
– Connect the GPS module’s TX pin to the Arduino’s digital pin 2 (RX)
– Connect the GPS module’s RX pin to the Arduino’s digital pin 3 (TX)
– Connect the GPS module’s VCC pin to the Arduino’s 5V pin
– Connect the GPS module’s GND pin to the Arduino’s GND pin

Code:

#include <SoftwareSerial.h>

SoftwareSerial gpsSerial(2, 3); // RX, TX

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

void loop() {
  if (gpsSerial.available()) {
    char c = gpsSerial.read();
    Serial.print(c);
  }
}

In this code, we create a Software Serial object called gpsSerial using digital pins 2 and 3. We initialize both the hardware serial port and the Software Serial port at a baud rate of 9600.

In the loop() function, we check if there is data available on the Software Serial port using the available() function. If there is data available, we read it using the read() function and print it to the serial monitor using the print() function.

Project 2: Controlling an LCD Display

In this project, we will use Software Serial communication to control an LCD display connected to the Arduino board. We will send commands to the LCD display over the Software Serial port to display text and change the cursor position.

Hardware Required:
– Arduino UNO board
– 16×2 LCD display
– 10K potentiometer
– Jumper wires

Connections:
– Connect the LCD display’s VSS pin to the Arduino’s GND pin
– Connect the LCD display’s VDD pin to the Arduino’s 5V pin
– Connect the LCD display’s VO pin to the potentiometer’s middle pin
– Connect the potentiometer’s outer pins to the Arduino’s 5V and GND pins
– Connect the LCD display’s RS pin to the Arduino’s digital pin 2
– Connect the LCD display’s RW pin to the Arduino’s GND pin
– Connect the LCD display’s E pin to the Arduino’s digital pin 3
– Connect the LCD display’s D4, D5, D6, and D7 pins to the Arduino’s digital pins 4, 5, 6, and 7, respectively

Code:

#include <SoftwareSerial.h>
#include <LiquidCrystal.h>

SoftwareSerial lcdSerial(2, 3); // RX, TX
LiquidCrystal lcd(4, 5, 6, 7);

void setup() {
  lcdSerial.begin(9600);
  lcd.begin(16, 2);
}

void loop() {
  if (lcdSerial.available()) {
    char command = lcdSerial.read();
    if (command == 'c') {
      lcd.clear();
    } else if (command == 'p') {
      int row = lcdSerial.parseInt();
      int col = lcdSerial.parseInt();
      lcd.setCursor(col, row);
    } else {
      lcd.print(command);
    }
  }
}

In this code, we create a Software Serial object called lcdSerial using digital pins 2 and 3. We also create an instance of the LiquidCrystal object, specifying the digital pins connected to the LCD display.

We initialize the Software Serial port and the LCD display in the setup() function.

In the loop() function, we check if there is data available on the Software Serial port. If there is data available, we read it using the read() function. If the received command is ‘c’, we clear the LCD display using the clear() function. If the command is ‘p’, we expect two integers representing the row and column where we want to set the cursor position, which we read using the parseInt() function and set using the setCursor() function. Otherwise, we assume the received data is text to be displayed on the LCD, so we print it using the print() function.

FAQ

1. Can I use Software Serial and hardware serial communication simultaneously?

Yes, you can use both Software Serial and hardware serial communication simultaneously on the Arduino board. However, keep in mind that using Software Serial may interfere with other libraries or functions that use interrupts or timers.

2. What is the maximum baud rate supported by Software Serial Arduino?

The maximum baud rate supported by Software Serial Arduino is 115200. However, it is recommended to use lower baud rates (e.g., 9600) for more reliable communication, especially with longer cable lengths.

3. Can I use multiple Software Serial ports on the same Arduino board?

Yes, you can create multiple Software Serial objects on the same Arduino board, each using a different pair of digital pins for communication. However, the more Software Serial ports you use, the more processing power and memory will be consumed.

4. Is Software Serial Arduino compatible with all Arduino boards?

Software Serial Arduino is compatible with most Arduino boards, including the UNO, Mega, and Nano. However, some boards, such as the Arduino Due, do not support Software Serial communication due to differences in their architecture.

5. Can I use Software Serial Arduino to communicate with other devices besides sensors and modules?

Yes, you can use Software Serial Arduino to communicate with any device that supports serial communication, such as other microcontrollers, computers, or even smartphones using a Bluetooth module.

Conclusion

Software Serial Arduino is a powerful tool that enables you to expand the communication capabilities of your Arduino board. By creating additional serial ports using software, you can connect and communicate with multiple devices simultaneously, even if your board has only one hardware serial port.

In this article, we covered the basics of Software Serial Arduino, including how to use it in your code, its advantages and disadvantages, and some example projects demonstrating its capabilities. We also answered some frequently asked questions about Software Serial Arduino.

With this knowledge, you should be well-equipped to start using Software Serial Arduino in your own projects. Whether you’re connecting sensors, controlling displays, or communicating with other devices, Software Serial Arduino provides a flexible and easy-to-use solution for serial communication on the Arduino platform.