/*
  Forum: https://forum.arduino.cc/t/vier-hc-sr-04-ultraschallsensoren-an-nur-5-pins-geht-das/1401048
  Wokwi: https://wokwi.com/projects/438736643634636801

  2025/08/08
  ec2021

*/

constexpr byte S0 {2};
constexpr byte S1 {3};
constexpr byte S2 {6};
constexpr byte COMOut {4};
constexpr byte COMIn {5};
constexpr byte numSensors {6};

void setup() {
  Serial.begin(115200);
  pinMode(S0, OUTPUT);
  pinMode(S1, OUTPUT);
  pinMode(S2, OUTPUT);

  pinMode(COMOut, OUTPUT);
  pinMode(COMIn, INPUT);
}

void loop() {
  for (int i = 0; i < numSensors; i++) {
    trigger(i);
    // Read the result:
    int duration = pulseIn(COMIn, HIGH);
    Serial.print("Sensor No. ");
    Serial.print(i + 1);
    Serial.print("\tDistance [cm]: ");
    Serial.println(duration / 58);
    delay(500);
  }

}

void trigger(int no) {
  digitalWrite(S0, no & 0x01);
  digitalWrite(S1, no & 0x02);
  digitalWrite(S2, no & 0x04);
  digitalWrite(COMOut, HIGH);
  delayMicroseconds(10);
  digitalWrite(COMOut, LOW);
}