Build a Web-Enabled Arduino Thermometer with DS18B20 Sensor

Components and supplies

Arduino UNO

PHPoC WiFi Shield for Arduino

we can use PHPoC Shield instead

Adafruit DS18B20 temperature sensor

Seeed Resistor 4.7k ohm

Heat Shrink Tube

About this project

If you are a beginner, you can learn about wifi and sensor in Arduino - Wifi and Arduino - DS18B20 temperature sensor tutorials

I made a similar project using only PHPoC here.

Demo

Data Flow

Arduino ---> PHPoC WiFi Shield ---> Web browser

Arduino reads temperature from sensor and send the temperature value to PHPoC WiFi Shield. When receiving the temperature value, PHPoC WiFi Shield send it to Web Browser via websocket. JavaScript function visualizes the temperature value on UI.

Note that: PHPoC shield has a built-in program to pass data from Arduino to web browser. Therefore, we don't need to care about it.

What We Need to Do

Set WiFi information for PHPoC shield (SSID and password)
Upload new UI to PHPoC shield
Write Arduino code

Setting WiFi Information for PHPoC Shield

See this instruction.

Upload new Web UI to PHPoC Shield

Download PHPoC source code remote_thermometer.php (on code section).
Upload it to PHPoC shield using PHPoC debugger according to this instruction.

Write Arduino Code

Install three following libraries: PHPoC Library for Arduino , OneWire and Dallas Temperature (see instruction ).
Upload Arduino code (on code section) to Arduino

Testing

Click serial button on Arduino IDE to see the IP address.
Open web browser, type http:// replace_ip_address/remote_thermometer.php
Click connect button and test it.

The Best Arduino Starter Kit for Beginner

If you are looking for an Arduino kit, see The Best Arduino Kit for Beginners

Function References

Serial.begin()
Serial.println()
delay()
millis()
for loop
while loop
if else
loop()
setup()
String.toInt()
String.substring()
String.indexOf()
String.remove()
String.equals()

Code

Arduino Code
remote_thermometer.php

Arduino CodeArduino

#include <OneWire.h>
#include <DallasTemperature.h>
#include "SPI.h"
#include "Phpoc.h"

// Data wire is plugged into port 8 on the Arduino
OneWire oneWire(8);
DallasTemperature sensors(&oneWire);

PhpocServer server(80);
boolean alreadyConnected = false; 

void setup() {
	Serial.begin(9600);
	while(!Serial)
		;
	
	sensors.begin();

	Phpoc.begin(PF_LOG_SPI | PF_LOG_NET);

	server.beginWebSocket("thermometer");

	Serial.print("WebSocket server address : ");
	Serial.println(Phpoc.localIP());	
}

void loop() {
	// when the client sends the first byte, say hello:
	PhpocClient client = server.available();
	
	if (client) {
		sensors.requestTemperatures(); 
		float temp = sensors.getTempCByIndex(0);
		String txtMsg = String(temp) + "\r\n";  
		char buf[txtMsg.length()];
		txtMsg.toCharArray(buf, txtMsg.length());
		server.write(buf, txtMsg.length());
		delay(300);
	}
}

remote_thermometer.phpPHP

This file provide web user interface. Upload this file to PHPoC Wifi Shield or PHPoC Shield according to the described instruction.

<!DOCTYPE html>
<html>
<head>
<title>Arduino - PHPoC Shield - Thermometer</title>
<meta name="viewport" content="width=device-width, initial-scale=0.7, maximum-scale=0.7">
<meta charset="utf-8">
<style>
body { text-align: center; font-size: width/2pt; }
h1 { font-weight: bold; font-size: width/2pt; }
h2 { font-weight: bold; font-size: width/2pt; }
button { font-weight: bold; font-size: width/2pt; }
</style>
<script>
var canvas_width = 200, canvas_height = 450;

var ws;
var buffer = "";

function init()
{
	var canvas = document.getElementById("remote");
	//canvas.style.backgroundColor = "#999999";
	canvas.width = canvas_width;
	canvas.height = canvas_height;
	
	var ctx = canvas.getContext("2d");
	
	ctx.translate(canvas_width/2, canvas_height - 80);
	
	update_view(0);
}
function connect_onclick()
{
	if(ws == null)
	{
		var ws_host_addr = "<?echo _SERVER("HTTP_HOST")?>";
		if((navigator.platform.indexOf("Win") != -1) && (ws_host_addr.charAt(0) == "["))
		{
			// network resource identifier to UNC path name conversion
			ws_host_addr = ws_host_addr.replace(/[\[\]]/g, '');
			ws_host_addr = ws_host_addr.replace(/:/g, "-");
			ws_host_addr += ".ipv6-literal.net";
		}
		
		ws = new WebSocket("ws://" + ws_host_addr + "/thermometer", "text.phpoc");
		document.getElementById("ws_state").innerHTML = "CONNECTING";
		ws.onopen = ws_onopen;
		ws.onclose = ws_onclose;
		ws.onmessage = ws_onmessage;
		//ws.binaryType = "arraybuffer";
	}
	else
		ws.close();
}
function ws_onopen()
{
	document.getElementById("ws_state").innerHTML = "<font color='blue'>CONNECTED</font>";
	document.getElementById("bt_connect").innerHTML = "Disconnect";
	ws.send("B\r\n");
	update_view(0);
}
function ws_onclose()
{
	document.getElementById("ws_state").innerHTML = "<font color='gray'>CLOSED</font>";
	document.getElementById("bt_connect").innerHTML = "Connect";
	ws.onopen = null;
	ws.onclose = null;
	ws.onmessage = null;
	ws = null;
	update_view(0);
}
function ws_onmessage(e_msg)
{
	e_msg = e_msg || window.event; // MessageEvent
	
	console.log(e_msg.data);
	
	update_view(parseFloat(e_msg.data));
}
function update_view(temp)
{
	var canvas = document.getElementById("remote");
	var ctx = canvas.getContext("2d");
	
	var radius = 70;
	var offset = 5;
	var width = 45;
	var height = 330;
 
	ctx.clearRect(-canvas_width/2, -350, canvas_width, canvas_height);
	
	if(ws != null)
	{
		ctx.strokeStyle="blue";
		ctx.fillStyle="blue";
	}
	else
	{
		ctx.strokeStyle="Gray";
		ctx.fillStyle="Gray";
	}
	
	//5-step Degree
	var x = -width/2;
	ctx.lineWidth=2;
	for (var i = 0; i <= 100; i+=5)
	{
		var y = -(height - radius)*i/100 - radius - 5;
		ctx.beginPath();
		ctx.lineTo(x, y);
		ctx.lineTo(x - 20, y);
		ctx.stroke();
	}
	
	//20-step Degree
	ctx.lineWidth=5;
	for (var i = 0; i <= 100; i+=20)
	{
		var y = -(height - radius)*i/100 - radius - 5;
		ctx.beginPath();
		ctx.lineTo(x, y);
		ctx.lineTo(x - 25, y);
		ctx.stroke();
		
		ctx.font="20px Georgia";
		ctx.textBaseline="middle"; 
		ctx.textAlign="right";
		ctx.fillText(i.toString(), x - 35, y);
	}
	
	// shape
	ctx.lineWidth=16;
	ctx.beginPath();
	ctx.arc(0, 0, radius, 0, 2 * Math.PI);
	ctx.stroke();
	
	ctx.beginPath();
	ctx.rect(-width/2, -height, width, height); 
	ctx.stroke();
	
	ctx.beginPath();
	ctx.arc(0, -height, width/2, 0, 2 * Math.PI);
	ctx.stroke();
	
	ctx.fillStyle="#e6e6ff";
	ctx.beginPath();
	ctx.arc(0, 0, radius, 0, 2 * Math.PI);
	ctx.fill();
	
	ctx.beginPath();
	ctx.rect(-width/2, -height, width, height); 
	ctx.fill();
	
	ctx.beginPath();
	ctx.arc(0, -height, width/2, 0, 2 * Math.PI);
	ctx.fill();
	
	// temperature value
	if(ws != null)
		ctx.fillStyle="#ff1a1a";
	else
		ctx.fillStyle="Gray";
		
	ctx.beginPath();
	ctx.arc(0, 0, radius - offset, 0, 2 * Math.PI);
	ctx.fill();
	
	temp = Math.round(temp);
	var y = (height - radius)*temp/100.0 + radius + 5; 
	ctx.beginPath();
	ctx.rect(-width/2 + offset, -y, width - 2*offset, y); 
	ctx.fill();
	
	if(ws != null)
	{
		ctx.fillStyle="white";
		ctx.font="bold 34px Georgia";
		ctx.textBaseline="middle"; 
		ctx.textAlign="center";
		ctx.fillText(temp.toString() + "°C", 0, 0);
	}
}

window.onload = init;
</script>
</head>

<body>

<p>
<h1>Arduino - Web Thermometer</h1>
</p>

<canvas id="remote"></canvas>

<h2>
<p>
WebSocket : <span id="ws_state">null</span>
</p>
<button id="bt_connect" type="button" onclick="connect_onclick();">Connect</button>
</h2>

</body>
</html>

Schematics

1. Stack PHPoC wifi shield or PHPoC shield on Arduino
2. Wiring like below image Build a Web-Enabled Arduino Thermometer with DS18B20 Sensor

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Manufacturing process

3D printing

Automation Control System

Industrial Technology