ultrasonic.ino

// https://docs.google.com/presentation/d/1rrYLHVR3_Fc7mmvc8I8zGOhtoBDN02RjF_-aecimZdg/edit?usp=sharing
#include <NewPing.h>
#define TRIGGER_PIN  12  // Arduino pin tied to trigger pin on the ultrasonic sensor.
#define ECHO_PIN     11  // Arduino pin tied to echo pin on the ultrasonic sensor.
#define MAX_DISTANCE 100 // Maximum distance we want to ping for (in centimeters). Maximum sensor
#define US_ROUNDTRIP_CM 58

void setup() {
    NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE); // NewPing setup of pins and maximum distance.
    pinMode(ECHO_PIN, OUTPUT);// Open serial monitor at 115200 baud to see ping results.
}


void loop() {
    unsigned int uS = sonar.ping(); // Send ping, get ping time in microseconds (uS).

    unsigned int distance = uS / US_ROUNDTRIP_CM;

    Serial.print("Ping: ");
    Serial.print(distance); // Convert ping time to distance in cm and print result (0 = outside set distance range)
    Serial.println("cm");

    if(distance < 30 && distance > 0 ){
        // distance from 0-30 cm
    }
}