IoT-Bus HC-SR04 Thing

/*
*  Arduino framework
*/

#include <arduino.h>

/*
*  MOZ IoT
*/
#include <Thing.h>
#include <WebThingAdapter.h>

/*
*  Graphics
*/
#include "TFT_eSPI.h" // Hardware-specific library

TFT_eSPI display = TFT_eSPI();

WebThingAdapter* adapter;

const char* sensorTypes[] = {"LevelSensor", nullptr};
ThingDevice hcsr04("HC-SR04", "HC-SR04", sensorTypes);
ThingProperty distance("distance", "Distance in cm", NUMBER, "LevelProperty", "Distance", "in", "false");
ThingPropertyValue measurement;

/*
*  WiFi ssid and password
*/
const char* ssid = ".........";
const char* password = "........";

/*
*  HC-SR04
*/
int trigPin = 2;    // Trigger
int echoPin = 4;    // Echo
long duration, cm, inches;

/*
*  displayString helper function to draw text on
*  the TFT display
*/
const int textHeight = 18;
const int textWidth = 18;
const int width = 320;
const int height = 240;

String last, current; // current and last values of text

void displayString(const String& str, int color) {
    int len = str.length()+1;
    int strWidth = len * textWidth;
    int strHeight = textHeight;
    int scale = width / strWidth;

    int x = width / 2 - (strWidth * scale / 2);
    int y = height / 2 + (strHeight * scale / 2);

    display.setFreeFont(&FreeSans18pt7b);
    display.setRotation(1);
    display.setTextColor(color);
    display.setTextSize(scale);
    display.setCursor(x, y);
    display.println(str);
    Serial.println(str);
}

/*
*  First-time initialization
*/

void setup() {
    // Start serial monitor - make sure same speed as monitor
    Serial.begin (115200);

    // HC-SR04 pins
    pinMode(trigPin, OUTPUT);
    pinMode(echoPin, INPUT);

    // Turn on display
    pinMode(33, OUTPUT); // turn on the IoT-Bus Display
    digitalWrite(33, HIGH);

    // Start display and clear
    display.begin();
    display.fillScreen(ILI9341_BLACK);

    // Start WiFi
    WiFi.mode(WIFI_STA);
    WiFi.begin(ssid, password);
    Serial.println("");

    // Wait for connection
    while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
    }

    Serial.println("");
    Serial.print("Connected to ");
    Serial.println(ssid);
    Serial.print("IP address: ");
    Serial.println(WiFi.localIP());

    // Initialize MOZ IoT thing
    adapter = new WebThingAdapter("textdisplayer", WiFi.localIP());
    measurement.number = -1;
    distance.setValue(measurement);
    hcsr04.addProperty(&distance);
    adapter->addDevice(&hcsr04);
    adapter->begin();
}

void loop() {
    // The sensor is triggered by a HIGH pulse of 10 or more microseconds.
    // Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
    digitalWrite(trigPin, LOW);
    delayMicroseconds(5);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);

    // Read the signal from the sensor: a HIGH pulse whose
    // duration is the time (in microseconds) from the sending
    // of the ping to the reception of its echo off of an object.
    pinMode(echoPin, INPUT);
    duration = pulseIn(echoPin, HIGH);

    // Convert the time into a distance
    cm = (duration/2) / 29.1;     // Divide by 29.1 or multiply by 0.0343
    inches = (duration/2) / 74;   // Divide by 74 or multiply by 0.0135

    // Uncomment to display on serial monitor
    //  Serial.print(inches);
    //  Serial.print("in, ");
    //  Serial.print(cm);
    //  Serial.print("cm");
    //  Serial.println();
    if(cm >= 400 || cm < 2){
        current = "Out of range";
    }
    else{
        current = String(inches) + " in";
    }
    if (current != last){
        displayString(last, ILI9341_BLACK);    // clear old text by writing it black
        displayString(current, ILI9341_WHITE); // write the new value
        measurement.number = inches;
        distance.setValue(measurement);
        adapter->update();                     // update the MOZ IoT thing
        last = current;                        // remember the last write to be able to clear it
        delay(500);                            // vary to suit
    }
}