/*          ULTRASONIC SENSOR LAB
  
A NOTE about bats.

Ultrasonic sensors use the same system as the modern Bat.  Echolocation. 

Send out a sonic pulse (outside of human hearing range)

Then wait for the echo to return.

The longer the wait, the longer the distance.

*/

long reading; //Stores the value from the sensor

void setup() {
  Serial.begin(9600);   //Starts the Serial Monitor so we can see the values
  
  pinMode(3, OUTPUT);  //Trip Pin: Sends out the echolocation pulse
  pinMode(2, INPUT);   //Echo Pin: Listens for the echo
}

void loop() {
  //Sends out the sonic pulse
  digitalWrite(3, LOW);
  delayMicroseconds(2);
  digitalWrite(3, HIGH);
  delayMicroseconds(10);

  //Listens for the echo
  reading = pulseIn(2, HIGH);

  //Displays to the Serial Monitor
  Serial.println(reading);
}

/*
 What values do you get if your hand is in the sensor view range?

 Does the value change the further or closer you get
 Part 2

 Add an LED or Piezo speaker to your breadboard.
 Add the code to activate the light and/or speaker if the sensor detects an object.
 */