How to Use the CD74HC4067 Multiplexer

How to Use the CD74HC4067 16-Channel Analog Multiplexer with Arduino

The CD74HC4067 is a 16-channel analog multiplexer that allows you to read or control multiple analog signals with just one microcontroller pin. It's an excellent solution for conserving GPIO pins when working with projects that require multiple inputs or outputs, such as sensor arrays, LED control, or data acquisition systems. In this post, we’ll walk through how to connect the CD74HC4067 to an Arduino, write basic code, and explore practical applications.

Required Components:

CD74HC4067 Multiplexer
Arduino (or any compatible microcontroller)
Sensors or input devices (e.g., potentiometers, buttons)
Jumper wires and a breadboard

Basic Steps:

Connect Power:
Link the VCC pin to 5V (or 3.3V depending on your Arduino version) and GND to ground.
Connect Control Pins:
Attach S0–S3 to digital pins on your microcontroller. These pins determine which channel is active.
Connect SIG Pin:
Connect the SIG pin to an analog input or output pin on the microcontroller (e.g., A0).
Connect Inputs/Outputs:
Attach up to 16 analog signals to the C0–C15 pins on the multiplexer.
Write Code:
Use the control pins to select the desired channel. You can refer to the truth table in the datasheet for the corresponding pin combinations.

Example Arduino Code

This simple example reads an analog value from each channel and displays it in the serial monitor:

int S0 = 2; // Control pin S0

int S1 = 3; // Control pin S1

int S2 = 4; // Control pin S2

int S3 = 5; // Control pin S3

int SIG = A0; // Signal pin

int channels = 16;

void setup() {

pinMode(S0, OUTPUT);

pinMode(S1, OUTPUT);

pinMode(S2, OUTPUT);

pinMode(S3, OUTPUT);

Serial.begin(9600);

}

void loop() {

for (int i = 0; i < channels; i++) {

digitalWrite(S0, i & 1);

digitalWrite(S1, (i >> 1) & 1);

digitalWrite(S2, (i >> 2) & 1);

digitalWrite(S3, (i >> 3) & 1);

int value = analogRead(SIG);

Serial.print("Channel ");

Serial.print(i);

Serial.print(": ");

Serial.println(value);

delay(500);

}

Applications of the 16-Channel Multiplexer

Here are a few practical applications where you can use the CD74HC4067 multiplexer:

Sensor Multiplexing: Read data from multiple sensors using a single analog input pin on your microcontroller.
LED Control: Power multiple LEDs while conserving I/O pins.
Data Acquisition: Collect signals from various sensors for monitoring systems.
Switch Expansion: Connect several buttons or toggle switches to the same microcontroller for additional inputs.

Why Use a Multiplexer?

Space Efficiency: Saves GPIO pins on your microcontroller, which is useful for devices with limited I/O capabilities.
Cost-Effective: No need for extra hardware components to expand your system’s input/output capabilities.
Flexible: Works well with both analog and digital signals, making it suitable for a wide range of projects.

Conclusion

The CD74HC4067 multiplexer is an ideal solution for projects that require multiple input or output channels without overwhelming your microcontroller’s available pins. Whether you're working on data acquisition systems, building a smart home project, or experimenting with sensors, this component can enhance the efficiency and scalability of your designs. Understanding its functionality and implementing it in your projects will allow you to save valuable resources and increase the flexibility of your designs.

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