bfritscher/ultrasound.ino

## ultrasound.ino
/*********
  ESP8266 Server + HC-SR04 ultrasound

  required libraries:
  - https://github.com/me-no-dev/ESPAsyncTCP
  - https://github.com/me-no-dev/ESPAsyncWebServer

  Adapted from

  Rui Santos
  Complete project details at https://RandomNerdTutorials.com/esp8266-nodemcu-hc-sr04-ultrasonic-arduino/
  Complete project details at https://randomnerdtutorials.com/esp8266-nodemcu-access-point-ap-web-server/


  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files.

  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
*********/

// Import required libraries
#include <Arduino.h>
#include <ESP8266WiFi.h>
#include <Hash.h>
#include <ESPAsyncTCP.h>
#include <ESPAsyncWebServer.h>

const char* ssid     = "ESP8266-Access-Point";
// const char* password = "123456789";

const int trigPin = 12;
const int echoPin = 14;

//define sound velocity in cm/uS /2
#define HALF_SOUND_VELOCITY 0.0171

long duration;
float distanceCm;

// Create AsyncWebServer object on port 80
AsyncWebServer server(80);

// Generally, you should use "unsigned long" for variables that hold time
// The value will quickly become too large for an int to store
unsigned long previousMillis = 0;    // will store last time DHT was updated

// Updates DHT readings every 1 seconds
const long interval = 1000;

const char index_html[] PROGMEM = R"rawliteral(
<!DOCTYPE HTML><html>
<head>
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <style>
    html {
     font-family: Arial;
     display: inline-block;
     margin: 0px auto;
     text-align: center;
    }
    h2 { font-size: 3.0rem; }
    p { font-size: 3.0rem; }
    .units { font-size: 1.2rem; }
    .dht-labels{
      font-size: 1.5rem;
      vertical-align:middle;
      padding-bottom: 15px;
    }
  </style>
</head>
<body>
  <h2>ESP8266 Server</h2>
  <p>
    <span class="dht-labels">Distance</span>
    <span id="distance">%DISTANCE%</span>
    <span class="units">cm</span>
  </p>
</body>
<script>
setInterval(function ( ) {
  var xhttp = new XMLHttpRequest();
  xhttp.onreadystatechange = function() {
    if (this.readyState == 4 && this.status == 200) {
      document.getElementById("distance").innerHTML = this.responseText;
    }
  };
  xhttp.open("GET", "/distance", true);
  xhttp.send();
}, 1000 ) ;
</script>
</html>)rawliteral";

// Replaces placeholder with DHT values
String processor(const String& var){
  if(var == "DISTANCE"){
    return String(distanceCm);
  }
  return String();
}

void setup(){
  // Serial port for debugging purposes
  Serial.begin(115200);
  pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
  pinMode(echoPin, INPUT); // Sets the echoPin as an Input
  Serial.print("Setting AP (Access Point)…");
  // Remove the password parameter, if you want the AP (Access Point) to be open
  WiFi.softAP(ssid);

  IPAddress IP = WiFi.softAPIP();
  Serial.print("AP IP address: ");
  Serial.println(IP);

  // Print ESP8266 Local IP Address
  Serial.println(WiFi.localIP());

  // Route for root / web page
  server.on("/", HTTP_GET, [](AsyncWebServerRequest *request){
    request->send_P(200, "text/html", index_html, processor);
  });
  server.on("/distance", HTTP_GET, [](AsyncWebServerRequest *request){
    request->send_P(200, "text/plain", String(distanceCm).c_str());
  });

  // Start server
  server.begin();
}

void loop(){
  unsigned long currentMillis = millis();
  if (currentMillis - previousMillis >= interval) {
    // Clears the trigPin
    digitalWrite(trigPin, LOW);
    delayMicroseconds(2);
    // Sets the trigPin on HIGH state for 10 micro seconds
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);

    // Reads the echoPin, returns the sound wave travel time in microseconds
    duration = pulseIn(echoPin, HIGH);

    // Calculate the distance
    distanceCm = duration * HALF_SOUND_VELOCITY;

    // Prints the distance on the Serial Monitor
    Serial.print("Distance (cm): ");
    Serial.println(distanceCm);
  }
}
	/*********
	ESP8266 Server + HC-SR04 ultrasound

	required libraries:
	- https://github.com/me-no-dev/ESPAsyncTCP
	- https://github.com/me-no-dev/ESPAsyncWebServer

	Adapted from

	Rui Santos
	Complete project details at https://RandomNerdTutorials.com/esp8266-nodemcu-hc-sr04-ultrasonic-arduino/
	Complete project details at https://randomnerdtutorials.com/esp8266-nodemcu-access-point-ap-web-server/


	Permission is hereby granted, free of charge, to any person obtaining a copy
	of this software and associated documentation files.

	The above copyright notice and this permission notice shall be included in all
	copies or substantial portions of the Software.
	*********/

	// Import required libraries
	#include <Arduino.h>
	#include <ESP8266WiFi.h>
	#include <Hash.h>
	#include <ESPAsyncTCP.h>
	#include <ESPAsyncWebServer.h>

	const char* ssid = "ESP8266-Access-Point";
	// const char* password = "123456789";

	const int trigPin = 12;
	const int echoPin = 14;

	//define sound velocity in cm/uS /2
	#define HALF_SOUND_VELOCITY 0.0171

	long duration;
	float distanceCm;

	// Create AsyncWebServer object on port 80
	AsyncWebServer server(80);

	// Generally, you should use "unsigned long" for variables that hold time
	// The value will quickly become too large for an int to store
	unsigned long previousMillis = 0; // will store last time DHT was updated

	// Updates DHT readings every 1 seconds
	const long interval = 1000;

	const char index_html[] PROGMEM = R"rawliteral(
	<!DOCTYPE HTML><html>
	<head>
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<style>
	html {
	font-family: Arial;
	display: inline-block;
	margin: 0px auto;
	text-align: center;
	}
	h2 { font-size: 3.0rem; }
	p { font-size: 3.0rem; }
	.units { font-size: 1.2rem; }
	.dht-labels{
	font-size: 1.5rem;
	vertical-align:middle;
	padding-bottom: 15px;
	}
	</style>
	</head>
	<body>
	<h2>ESP8266 Server</h2>
	<p>
	<span class="dht-labels">Distance</span>
	<span id="distance">%DISTANCE%</span>
	<span class="units">cm</span>
	</p>
	</body>
	<script>
	setInterval(function ( ) {
	var xhttp = new XMLHttpRequest();
	xhttp.onreadystatechange = function() {
	if (this.readyState == 4 && this.status == 200) {
	document.getElementById("distance").innerHTML = this.responseText;
	}
	};
	xhttp.open("GET", "/distance", true);
	xhttp.send();
	}, 1000 ) ;
	</script>
	</html>)rawliteral";

	// Replaces placeholder with DHT values
	String processor(const String& var){
	if(var == "DISTANCE"){
	return String(distanceCm);
	}
	return String();
	}

	void setup(){
	// Serial port for debugging purposes
	Serial.begin(115200);
	pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
	pinMode(echoPin, INPUT); // Sets the echoPin as an Input
	Serial.print("Setting AP (Access Point)…");
	// Remove the password parameter, if you want the AP (Access Point) to be open
	WiFi.softAP(ssid);

	IPAddress IP = WiFi.softAPIP();
	Serial.print("AP IP address: ");
	Serial.println(IP);

	// Print ESP8266 Local IP Address
	Serial.println(WiFi.localIP());

	// Route for root / web page
	server.on("/", HTTP_GET, [](AsyncWebServerRequest *request){
	request->send_P(200, "text/html", index_html, processor);
	});
	server.on("/distance", HTTP_GET, [](AsyncWebServerRequest *request){
	request->send_P(200, "text/plain", String(distanceCm).c_str());
	});

	// Start server
	server.begin();
	}

	void loop(){
	unsigned long currentMillis = millis();
	if (currentMillis - previousMillis >= interval) {
	// Clears the trigPin
	digitalWrite(trigPin, LOW);
	delayMicroseconds(2);
	// Sets the trigPin on HIGH state for 10 micro seconds
	digitalWrite(trigPin, HIGH);
	delayMicroseconds(10);
	digitalWrite(trigPin, LOW);

	// Reads the echoPin, returns the sound wave travel time in microseconds
	duration = pulseIn(echoPin, HIGH);

	// Calculate the distance
	distanceCm = duration * HALF_SOUND_VELOCITY;

	// Prints the distance on the Serial Monitor
	Serial.print("Distance (cm): ");
	Serial.println(distanceCm);
	}
	}