/* 
Code for testing Skitter Ultrasonic
by Jonathan Lane, AndyMark Inc
created for Purdue University
*/

#define echoPin 11  // attach pin A4 ESP32 to pin Echo of Ultra
#define trigPin 12   //attach pin A5 ESP32 to pin Trig of Ultra

// defines variables
long duration; // variable for the duration of sound wave travel
int distance; // variable for the distance measurement

void setup() 
{
  pinMode(trigPin, OUTPUT); // Sets the trigPin as an OUTPUT
  pinMode(echoPin, INPUT); // Sets the echoPin as an INPUT
  Serial.begin(9600); // // Serial Communication is starting with 9600 of baudrate speed
  Serial.println("Skitter Ultrasonic Sensor Test"); // print some text in Serial Monitor
  Serial.println("with ESP32");
}

void loop() 
{
  // Clears the trigPin condition
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  
  // Sets the trigPin HIGH (ACTIVE) for 10 microseconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);
  
  // Calculating the distance
  distance = duration * 0.034 / 2; // Speed of sound wave divided by 2 (there and back)
  
  // Displays the distance on the Serial Monitor
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");
}