#include <Arduino.h>
#define SIG 7
#define EN 6

const uint8_t controlPins[] = { 2, 3, 4 };
const uint8_t ledPins[] = { 8, 9, 10 };

void setup() {
  // put your setup code here, to run once:
  for (int i = 0; i < 4; ++i)
  {
    pinMode(controlPins[i], OUTPUT);
    pinMode(ledPins[i], OUTPUT);
  }
  pinMode(EN, OUTPUT);
  pinMode(SIG, INPUT_PULLUP);
  digitalWrite(EN, 1);
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  byte data;
  for (byte i = 0; i < 8; i++) {
    data = readMux(i) /* Reads from channel i (returns HIGH or LOW) */;

    Serial.print("Push button at channel "); Serial.print(i + 1);
    Serial.print(" is "); Serial.println(data == LOW ? "pressed" : "not pressed");
    delay(50);
  }
  Serial.println();

  delay(1500);
}

int readMux(int channel)
{
  for(int i = 0; i < 3; i ++)
  {
    int b = channel >> i & 1;
    digitalWrite(controlPins[i], b);
    digitalWrite(ledPins[i], b);
    delay(3);
    // Serial.print(b);
    // Serial.print(" ");
  }
  // Serial.println();
  delay(100);
  int val = digitalRead(SIG);
  for(int i = 0; i < 3; i ++)
  {
    digitalWrite(controlPins[i], 0);
    digitalWrite(ledPins[i], 0);
  }
  return val;
}