Esquilo Air & HC-SR04 + 1602 LCD Tutorial

// HC-SR04 Ultrasonic Range Finder output to 1602A LCD

require("GPIO");
require("Capture");

dofile("sd:/LiquidCrystal.nut");

trigPin <- GPIO(13);  // HC-SR04 trigger pin (output)
echoPin <- Capture(1);  // HC-SR04 echo pin (input)

trigPin.output();

local duration;
local distance;

local lcd = LiquidCrystal(0x00, 12, 0, 11, 5, 4, 3, 2, 0, 0, 0, 0);

// set up the LCD's number of columns and rows: 
lcd.begin(16, 2, 0);

while (true) {
    lcd.clear();
    lcd.home();
    trigPin.low();
    delay(2);
    trigPin.high();
    delay(10);
    trigPin.low();
    echoPin.arm(0, CAPTURE_EDGE_RISING);
    duration = echoPin.read(0);
    //print("duration=" + duration);
    distance = (duration / 2) / 29.1;
    //print("distance=" + distance);
    // Print a message to the LCD.
    lcd.print("distance=" + distance);
    delay(500);
}