const int select[] = {2,3,4}; // pins connected to the 4051 input select lines
const int analogPin = 0; // the analog pin connected to multiplexer output
// this function returns the analog value for the given channel
int getValue( int channel)
{
 // set the selector pins HIGH and LOW to match the binary value of channel
 for(int bit = 0; bit < 3; bit++)
 {
 int pin = select[bit]; // the pin wired to the multiplexer select bit

 int isBitSet = bitRead(channel, bit); // true if given bit set in channel
 digitalWrite(pin, isBitSet);
 }
 return analogRead(analogPin);
}
void setup()
{
 for(int bit = 0; bit < 3; bit++)
 pinMode(select[bit], OUTPUT); // set the three select pins to output
 Serial.begin(9600);
}
void loop () {
 // print the values for each channel once per second
 for(int channel = 0; channel < 8; channel++)
 {
 int value = getValue(channel);
 Serial.print("Channel ");
 Serial.print(channel);
 Serial.print(" = ");
 Serial.println(value);
 }
 delay (1000);
}