Getting Started with pySerial: A Powerful Python Library

pySerial, a Powerful Python Library – A Beginner’s Guide for Python Newbies

In modern hardware development, serial communication is one of the common ways to connect different devices. Have you ever needed to communicate with external hardware (such as sensors, Arduino, Raspberry Pi, etc.) through your computer? If so, you will find that the pySerial Python library is extremely useful. It provides a simple way to interact with serial ports for reading and writing data.

For Python beginners, pySerial is a very easy-to-use library that helps you control and retrieve data from hardware devices. Today, we will teach you how to use pySerial for serial communication through a practical example.

What is pySerial?

pySerial is a Python library that provides access to serial ports (such as RS232, RS485, etc.). It allows Python programs to communicate with other hardware through serial ports, commonly used for reading sensor data, communicating with microcontrollers (like Arduino), and controlling devices.

With pySerial, you can easily send data to devices, receive data from devices, and control communication rates. Additionally, pySerial supports various serial protocols, including common ASCII and binary data transmission, making it powerful and flexible.

Installing pySerial

Before we start using pySerial, we need to install it. You can install it using Python’s package managerpip:

pip install pyserial

Once installed, you can import the pySerial library in your Python code and start serial communication.

Basic Usage Example: Communicating with Arduino

Assuming you have an Arduino board connected to your computer via USB, and you are running a program on the Arduino that sends sensor data through the serial port at regular intervals. We will read this data using Python.

1. Connect Arduino and Check Serial Port

First, make sure your Arduino device is connected to the computer via USB. You can check the serial port in the Device Manager (Windows) or through the command line (Linux/macOS). Let’s assume the Arduino’s serial port isCOM3 (Windows) or/dev/ttyUSB0 (Linux/macOS).

2. Write Python Code to Communicate with Arduino

import serial
import time

# Set up serial port, baud rate, timeout, etc.
ser = serial.Serial('COM3', 9600, timeout=1)  # Serial port on Windows
# ser = serial.Serial('/dev/ttyUSB0', 9600, timeout=1)  # Serial port on Linux/macOS

time.sleep(2)  # Give Arduino some time to initialize

# Read data sent from Arduino
while True:
    if ser.in_waiting > 0:  # If there is data to read
        data = ser.readline().decode('utf-8').strip()  # Read a line of data and decode
        print(f"Received data: {data}")

ser.close()  # Close the serial connection

3. Explaining the Code

serial.Serial(): Initializes the serial connection; COM3 is our device’s serial port, 9600 is the baud rate for communication. timeout=1 indicates a wait time of 1 second to read data.
time.sleep(2): Since Arduino needs some time to start and initialize, we give it 2 seconds to prepare.
ser.readline(): Reads each line of data sent from Arduino. The returned data is in byte format, so we need to use decode('utf-8') to convert byte data to string.
ser.close(): Remember to close the serial port connection after completing the task.

4. Run the Code

Run a simple program on the Arduino to send data. For example, the Arduino code is as follows:

void setup() {
  Serial.begin(9600);  // Initialize serial port, set baud rate to 9600
}

void loop() {
  int sensorValue = analogRead(A0);  // Read analog sensor data
  Serial.println(sensorValue);  // Send data to serial port
  delay(1000);  // Send data every second
}

When you run the Python code, you should see the data sent from Arduino every second through the serial port.

Advanced Usage

In addition to simple reading and writing of data, pySerial also supports some more advanced features:

Control Serial Port Parameters: You can adjust the serial port’s baud rate, data bits, stop bits, and other parameters by modifying the Serial object’s properties. For example, ser.baudrate, ser.bytesize, ser.parity, etc.
Binary Data Transmission: If you need to transmit binary data, you can use ser.write(bytearray) to send binary data and ser.read(size) to read a specified number of bytes.
Serial Communication Debugging: pySerial also supports flushing the buffer with ser.flush(), and checking if the serial port is successfully opened with ser.isOpen().

Conclusion

pySerial is a very powerful and easy-to-use Python library suitable for scenarios that require serial communication with external hardware. With just a few lines of code, you can start interacting with Arduino, sensors, or other serial devices. Whether you want to collect sensor data, control hardware devices, or communicate with other embedded systems, pySerial can provide great help.

Through today’s practical example, you should have a preliminary understanding of the basic usage of pySerial. Next, you can try more application scenarios to further enhance your Python skills.