This sample code is for Smart Blind Stick Tutorial.

smart_blind_stick.ino

#define TRIGPIN1  2
#define ECHOPIN1  3
#define TRIGPIN2  5
#define ECHOPIN2  6
#define PIEZO     8

// defines variables
long Duration1;
int Distance1;
long Duration2;
int Distance2;

void setup() {
  pinMode(TRIGPIN1, OUTPUT);
  pinMode(ECHOPIN1, INPUT);
  pinMode(TRIGPIN2, OUTPUT);
  pinMode(ECHOPIN2, INPUT);
  pinMode(PIEZO, OUTPUT);
  Serial.begin(9600);
}

void Activate1() {
  digitalWrite(TRIGPIN1, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIGPIN1, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIGPIN1, LOW);
}
void Activate2() {
  digitalWrite(TRIGPIN2, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIGPIN2, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIGPIN2, LOW);
}

void loop() {

  Activate1();
  Duration1 = pulseIn(ECHOPIN1, HIGH);
  Distance1 = Duration1 * 0.017;
  Activate2();
  Duration2 = pulseIn(ECHOPIN2, HIGH);
  Distance2 = Duration2 * 0.017;

  Serial.print(Distance1);
  Serial.print("      ");
  Serial.println(Distance2);

  if (Distance1 <= 10 || Distance2 <= 10) {
    tone(PIEZO, 1000, 300);
    delay(450);
  }
  else {
    noTone;
  }
}

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