Connecting multiple I2C devices in Arduino - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the I2C bus used for in Arduino projects?

I2C bus allows multiple devices to communicate using just two wires: SDA (data) and SCL (clock). It helps connect sensors, displays, and other modules easily.

beginner

How do you connect multiple I2C devices to an Arduino?

You connect all devices' SDA pins together to Arduino SDA, and all SCL pins together to Arduino SCL. Each device must have a unique address to avoid conflicts.

beginner

Why must each I2C device have a unique address?

Because the Arduino uses the address to talk to one device at a time. If two devices share the same address, the Arduino can't tell them apart and communication fails.

intermediate

What can you do if two I2C devices have the same address?

You can change the address if the device supports it, use an I2C multiplexer, or use separate I2C buses if your board supports it.

beginner

How do you scan for I2C devices connected to your Arduino?

You can run an I2C scanner sketch that tries all addresses and reports which devices respond. This helps find device addresses and check connections.

How many wires are needed to connect multiple I2C devices to an Arduino?

A Three wires: SDA, SCL, and CS

B One wire: SDA only

C Two wires: SDA and SCL

D Four wires: SDA, SCL, VCC, and GND

I2C uses two main wires for communication: SDA (data) and SCL (clock). Power and ground are separate but not part of the I2C bus.

What must be unique for each I2C device on the same bus?

A Clock speed

B Device address

C Wire color

D Power voltage

Each device must have a unique address so the Arduino can communicate with them individually.

If two devices share the same I2C address, what is a common solution?

A Change the Arduino board

B Connect devices to different pins

C Use different power supplies

D Use an I2C multiplexer

An I2C multiplexer lets you switch between devices with the same address by selecting which device is active.

What Arduino function can help find connected I2C devices?

A I2C scanner sketch

B digitalRead()

C analogWrite()

D Serial.begin()

An I2C scanner sketch tries all possible addresses and reports which devices respond.

Which pins on Arduino Uno are used for I2C communication?

A A4 (SDA) and A5 (SCL)

B D2 and D3

C D10 and D11

D A0 and A1

On Arduino Uno, analog pin 4 is SDA and analog pin 5 is SCL for I2C.

Explain how to wire multiple I2C devices to an Arduino and why unique addresses are important.

Think about how devices talk on the same two wires.

Describe methods to handle address conflicts when connecting multiple I2C devices.

Consider hardware and software solutions.