1. Un seul 74XX4051

/*
By : Thomas Ouellet Fredericks
Last Modified : 2014/09/30

Outputs over serial (baud 57600)
a 74XX4051 analog multiplexer connected to
digital pins 2,3,4 and analog pin 0
*/

// 74XX4051 ADDRESS PINS :
#define S0 2
#define  S1 3
#define  S2 4

// 74XX4051 ANALOG PIN :
#define  Z 0

void setup(){

        // CONFIGURE ADDRESS PINS
        pinMode(S0, OUTPUT);
        pinMode(S1, OUTPUT);
        pinMode(S2, OUTPUT);

        // CONFIGURE SERIAL
        Serial.begin(57600);
}

void loop () {

        // LOOP THROUGH ALL THE ADDRESSES
        for ( byte count = 0; count < 8 ; count++ ) {

                // SET THE ADDRESS
                digitalWrite(S0, bitRead(count, 0) );
                digitalWrite(S1, bitRead(count, 1) );
                digitalWrite(S2, bitRead(count, 2) );

                // READ THE ANALOG FOR THAT ADDRESS
                int reading = analogRead(Z);

                // SERIAL OUTPUT
                // print something like : A0-### value
                Serial.print("A0-");
                Serial.print(bitRead(count, 2));
                Serial.print(bitRead(count, 1));
                Serial.print(bitRead(count, 0));
                Serial.print(' ');
                Serial.println(reading);

                // 100 ms delay to not stress the serial communication.
                delay(100);
        }

}

1. Un seul 74XX4051

2. Cascade de 74XX4051

3. Autres ressources