CD4067 Multiplexer used to control LEDs

This tutorial will show how to control multiple LED outputs from a microcontroller using a CD4067  analog multiplexer.

This is a stub. More explanation will follow, but for now, here are schematics and code for Arduino.

Parts you’ll need:

  • CD4067B multiplexer
  • Arduino microcontroller
  • LEDs

The Circuit

CD4067B attached to an Arduino microcontroller

CD4067B attached to an Arduino microcontroller

The anodes of the LEDs connect to the multiplexer's outputs

The anodes of the LEDs connect to the multiplexer's outputs

The schematic

The schematic

The code

/*

 Multiplexer output example
 Controls 16 outputs, one at a time, using a CD4067B multiplexer.
 
 This sketch loops over the 16 channels of a CD4067 multiplexer, switching
 the input to each output channel in turn.  It then fades up and down the 
 input channel using analogWrite().
 
 The circuit:
 * CD4067 multiplexer attached as follows:
 - address pin A: digital I/O 2
 - address pin B: digital I/O 3
 - address pin C: digital I/O 4
 - address pin D: digital I/O 5
 - input pin: digital I/O pin 6
 - LEDs attached from each of the CD4067's output channels
 to ground
 
 created 21 May 2009
 by Tom Igoe
 
 http://www.tigoe.net/pcomp/code/category/arduinowiring/540 for more
 
 */

// put the address pin numbers in an array
// so they're easier to iterate over:
const int channel[] = {
  2, 3, 4, 5};

// the output pin channel (mux's input):
const int outputPin = 6;

void setup() {
  // set up all pins as output:
  for (int thisPin = 2; thisPin < 7; thisPin++) {
    pinMode(thisPin, OUTPUT);
  }
}

void loop() {
  // iterate over the 16 channels of the multiplexer:
  for (int thisChannel = 0; thisChannel < 16; thisChannel++) {
    // set the channel pins based on the channel you want:
    muxWrite(thisChannel);

    // fade the current channel up:
    for (int brightness = 0; brightness < 256; brightness++) {
      analogWrite(outputPin, brightness);
      delay(5);
    }
  }
}

void muxWrite(int whichChannel) {
  // iterate over the number of pins you're using:
  for (int thisPin = 0; thisPin < 4; thisPin++) {
    // calculate the state of this pin based on 
    // its bit value in whichChannel:
    int pinState = bitRead(whichChannel, thisPin);
    // turn the pin on or off:
    digitalWrite(channel[thisPin],pinState);
  }
}
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