Multiple I2C devices on same bus in Raspberry Pi - Mini Project: Build & Apply

Multiple I2C Devices on Same Bus

📖 Scenario: You have a Raspberry Pi connected to two I2C sensors on the same bus. You want to read data from both sensors without conflicts.

🎯 Goal: Write a Python program that communicates with two I2C devices on the same bus by specifying their addresses and reading data from each.

📋 What You'll Learn

Create a dictionary called devices with two I2C device addresses as keys and their names as values

Create a variable called bus_number and set it to 1 (the default I2C bus on Raspberry Pi)

Use a for loop with variables address and name to iterate over devices.items()

Inside the loop, create an SMBus object for bus_number and read a byte from each device address

Print the device name and the byte read in the format: Device {name} at address {address} returned {data}

💡 Why This Matters

🌍 Real World

Many projects use multiple sensors on the same I2C bus to save wiring and pins. This skill helps you manage multiple devices efficiently.

💼 Career

Understanding how to communicate with multiple I2C devices is important for embedded systems, IoT development, and hardware interfacing roles.

1

Create the I2C devices dictionary

Create a dictionary called devices with these exact entries: 0x40: 'Temperature Sensor' and 0x48: 'Light Sensor'

Raspberry Pi

# Create the devices dictionary with addresses and names
# Your code here

Hint

Use curly braces {} to create a dictionary with keys as addresses and values as names.

2

Set the I2C bus number

Create a variable called bus_number and set it to 1, which is the default I2C bus on Raspberry Pi

Raspberry Pi

devices = {0x40: 'Temperature Sensor', 0x48: 'Light Sensor'}
# Set the I2C bus number
# Your code here

Hint

Just assign the number 1 to the variable bus_number.

3

Read data from each I2C device

Use a for loop with variables address and name to iterate over devices.items(). Inside the loop, create an SMBus object for bus_number and read a byte from each device address using read_byte(address). Store the result in a variable called data

Raspberry Pi

devices = {0x40: 'Temperature Sensor', 0x48: 'Light Sensor'}
bus_number = 1
from smbus2 import SMBus
# Loop over devices and read a byte from each
# Your code here

Hint

Use for address, name in devices.items(): to loop. Use with SMBus(bus_number) as bus: to open the bus. Then read a byte with bus.read_byte(address).

4

Print the data from each device

Inside the for loop, add a print statement to display the device name, address, and data in this exact format: Device {name} at address {address} returned {data}

Raspberry Pi

devices = {0x40: 'Temperature Sensor', 0x48: 'Light Sensor'}
bus_number = 1
from smbus2 import SMBus

for address, name in devices.items():
    with SMBus(bus_number) as bus:
        data = bus.read_byte(address)
        # Print the device info and data
        # Your code here

Hint

Use an f-string in the print statement: print(f"Device {name} at address {address} returned {data}").