pyserial library usage in Raspberry Pi - Mini Project: Build & Apply

Reading Data from a Serial Port using pyserial

📖 Scenario: You have a Raspberry Pi connected to a sensor device that sends data through a serial port. You want to read this data using Python.

🎯 Goal: Build a Python program that opens a serial port, reads data from it, and prints the received messages.

📋 What You'll Learn

Use the pyserial library to open and read from the serial port.

Set the serial port to /dev/ttyUSB0 with baud rate 9600.

Read one line of data from the serial port.

Print the received data as a string.

💡 Why This Matters

🌍 Real World

Reading sensor data or communicating with microcontrollers via serial ports is common in Raspberry Pi projects.

💼 Career

Understanding serial communication is useful for embedded systems, IoT development, and hardware interfacing roles.

1

Setup the serial port connection

Import the serial module and create a serial.Serial object called ser with port '/dev/ttyUSB0' and baud rate 9600.

Raspberry Pi

# Import serial and create serial.Serial object ser
# Your code here

Hint

Use import serial to bring in the library. Then create ser = serial.Serial('/dev/ttyUSB0', 9600) to open the port.

2

Configure a timeout for reading

Set the timeout property of the ser object to 1 second to avoid waiting forever when reading.

Raspberry Pi

import serial
ser = serial.Serial('/dev/ttyUSB0', 9600)
# Set ser.timeout to 1
# Your code here

Hint

Set ser.timeout = 1 to make read operations wait at most 1 second.

3

Read one line of data from the serial port

Use ser.readline() to read one line of bytes from the serial port and decode it to a string called line.

Raspberry Pi

import serial
ser = serial.Serial('/dev/ttyUSB0', 9600)
ser.timeout = 1
# Read one line from ser and decode to string line
# Your code here

Hint

Use ser.readline() to get bytes, then .decode('utf-8') to convert to text, and .strip() to remove newline characters.

4

Print the received data

Print the string variable line to display the data read from the serial port.

Raspberry Pi

import serial
ser = serial.Serial('/dev/ttyUSB0', 9600)
ser.timeout = 1
line = ser.readline().decode('utf-8').strip()
# Print the line variable
# Your code here

Hint

Use print(line) to show the received message.