Published June 26, 2017 © GPL3+

Arduino - Web-Based Joystick

This project shows how to control devices from anywhere using web-based joystick on smartphone.

BeginnerFull instructions provided24,997

Things used in this project

Story

If you are a beginner, you can learn:

We can control everything with this project, but I took the servo motors as an example.

Demo

Wiring

Stack PHPoC WiFi shield or PHPoC Shield on Arduino
Connect pin GND and VCC of two servo motors to GND and 5V of Arduino, respectively. (pin IOREF of arduino can be used like 5V pin)
Connect pin signals of two servo motors to pin 8 and pin 9 of Arduino, respectively.

Data Flow

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

Web app on web browser will send the coordinate (after scaling) of touch or click event to PHPoC shield via WebSocket. When receiving the data, PHPoC shield automatically passes it to Arduino. Arduino controls two servo motors according to the data received from PHPoC Shield.

Note that: PHPoC shield has a built-in program to pass data from web browser to Arduino. 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_joystick.php (on code section).
Upload it to PHPoC shield using PHPoC debugger according to this instruction.

Write Arduino Code

Install PHPoC library for Arduino on Arduino IDE (see the instruction )
See source code in code section.

Try it

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

Similar Project but different hardware platform

This project does the same works but it used other hardware platform

The Best Arduino Starter Kit for Beginner

See The Best Arduino Kit for Beginners

Function References

Code

#include "SPI.h"
#include "Phpoc.h"
#include <Servo.h>

PhpocServer server(80);
Servo servo_x;
Servo servo_y;

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

	Phpoc.begin(PF_LOG_SPI | PF_LOG_NET);
	//Phpoc.begin();

	server.beginWebSocket("web_joystick");

	Serial.print("WebSocket server address : ");
	Serial.println(Phpoc.localIP());
	
	servo_x.attach(8);  // attaches the servo on pin 8 to the servo object
	servo_y.attach(9);  // attaches the servo on pin 9 to the servo object
	
	servo_x.write(90); 
	servo_y.write(90); 
	
}

void loop() {
	// wait for a new client:
	PhpocClient client = server.available();

	if (client) {
		String data = client.readLine();

		if(data){
			int pos = data.indexOf(':');
			long x = data.substring(0, pos).toInt();
			long y = data.substring(pos+1).toInt();
			
			Serial.print("x:");
			Serial.print(x);
			Serial.print(", y:");
			Serial.println(y);
			
			// scale  from [-100; 100] to [0; 180]
			long angle_x = (x + 100) * 180 /200;
			long angle_y = (y + 100) * 180 /200;
			
			servo_x.write(angle_x); 
			servo_y.write(angle_y); 
		}
	}
}

<!DOCTYPE html>
<html>
<head>
<title>Arduino - PHPoC Shield</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 = 500, canvas_height = 500;
var radius_base = 150;
var radius_handle = 72;
var radius_shaft = 120;
var range = canvas_width/2 - 10;
var step = 18;
var ws;
var joystick = {x:0, y:0};
var click_state = 0;

var ratio = 1;

function init()
{
	var width = window.innerWidth;
	var height = window.innerHeight;
	
	if(width < height)
		ratio = (width - 50) / canvas_width;
	else
		ratio = (height - 50) / canvas_width;
	
	canvas_width = Math.round(canvas_width*ratio);
	canvas_height = Math.round(canvas_height*ratio);
	radius_base = Math.round(radius_base*ratio);
	radius_handle = Math.round(radius_handle*ratio);
	radius_shaft = Math.round(radius_shaft*ratio);
	range = Math.round(range*ratio);
	step = Math.round(step*ratio);
	
	var canvas = document.getElementById("remote");
	//canvas.style.backgroundColor = "#999999";
	canvas.width = canvas_width;
	canvas.height = canvas_height;
 
	canvas.addEventListener("touchstart", mouse_down);
	canvas.addEventListener("touchend", mouse_up);
	canvas.addEventListener("touchmove", mouse_move);
	canvas.addEventListener("mousedown", mouse_down);
	canvas.addEventListener("mouseup", mouse_up);
	canvas.addEventListener("mousemove", mouse_move);
	
	var ctx = canvas.getContext("2d");
	ctx.translate(canvas_width/2, canvas_height/2);
	ctx.shadowBlur = 20;
	ctx.shadowColor = "LightGray";
	ctx.lineCap="round";
	ctx.lineJoin="round";
	
	update_view();
}
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 + "/web_joystick", "text.phpoc");
		document.getElementById("ws_state").innerHTML = "CONNECTING";
		ws.onopen = ws_onopen;
		ws.onclose = ws_onclose;
		ws.onmessage = ws_onmessage;
	}
	else
		ws.close();
}
function ws_onopen()
{
	document.getElementById("ws_state").innerHTML = "<font color='blue'>CONNECTED</font>";
	document.getElementById("bt_connect").innerHTML = "Disconnect";
	update_view();
}
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();
}
function ws_onmessage(e_msg)
{
	e_msg = e_msg || window.event; // MessageEvent
	
}
function send_data()
{
	var x = joystick.x, y = joystick.y;
	var joystick_range = range - radius_handle;
	x = Math.round(x*100/joystick_range);
	y = Math.round(-(y*100/joystick_range));
	
	if(ws != null)
		ws.send(x + ":" + y + "\r\n");
}
function update_view()
{
	var x = joystick.x, y = joystick.y;
	
	var canvas = document.getElementById("remote");
	var ctx = canvas.getContext("2d");
	
	ctx.clearRect(-canvas_width/2, -canvas_height/2, canvas_width, canvas_height);
	
	ctx.lineWidth = 3;
	ctx.strokeStyle="gray";
	ctx.fillStyle = "LightGray";
	ctx.beginPath();
	ctx.arc(0, 0, range, 0, 2 * Math.PI);
	ctx.stroke();
	ctx.fill();
	
	ctx.strokeStyle="black";
	ctx.fillStyle = "hsl(0, 0%, 35%)";
	ctx.beginPath();
	ctx.arc(0, 0, radius_base, 0, 2 * Math.PI);
	ctx.stroke();
	ctx.fill();
	
	ctx.strokeStyle="red";
	
	var lineWidth = radius_shaft;
	var pre_x = pre_y = 0;
	var x_end = x/5;
	var y_end = y/5;
	var max_count  = (radius_shaft - 10)/step;
	var count = 1;
	
	while(lineWidth >= 10)
	{
		var cur_x = Math.round(count * x_end / max_count);
		var cur_y = Math.round(count * y_end / max_count);
		console.log(cur_x);
		ctx.lineWidth = lineWidth;
		ctx.beginPath();
		ctx.lineTo(pre_x, pre_y);
		ctx.lineTo(cur_x, cur_y);
		ctx.stroke();
		
		lineWidth -= step;
		pre_x = cur_x;
		pre_y = cur_y;
		count++;
	}
	
	var x_start = Math.round(x / 3);
	var y_start = Math.round(y / 3);
	lineWidth += step;
	
	ctx.beginPath();
	ctx.lineTo(pre_x, pre_y);
	ctx.lineTo(x_start, y_start);
	ctx.stroke();
		
	count = 1;
	pre_x = x_start;
	pre_y = y_start;
	
	while(lineWidth < radius_shaft)
	{
		var cur_x = Math.round(x_start + count * (x - x_start) / max_count);
		var cur_y = Math.round(y_start + count * (y - y_start) / max_count);
		ctx.lineWidth = lineWidth;
		ctx.beginPath();
		ctx.lineTo(pre_x, pre_y);
		ctx.lineTo(cur_x, cur_y);
		ctx.stroke();
		
		lineWidth += step;
		pre_x = cur_x;
		pre_y = cur_y;
		count++;
	}
	
	var grd = ctx.createRadialGradient(x, y, 0, x, y, radius_handle);
	for(var i = 85; i >= 50; i-=5)
		grd.addColorStop((85 - i)/35, "hsl(0, 100%, "+ i + "%)");
		
	ctx.fillStyle = grd;
	ctx.beginPath();
	ctx.arc(x, y, radius_handle, 0, 2 * Math.PI);
	ctx.fill();
}
function process_event(event)
{
	var pos_x, pos_y;
	if(event.offsetX)
	{
		pos_x = event.offsetX - canvas_width/2;
		pos_y = event.offsetY - canvas_height/2;
	}
	else if(event.layerX)
	{
		pos_x = event.layerX - canvas_width/2;
		pos_y = event.layerY - canvas_height/2;
	}
	else
	{
		pos_x = (Math.round(event.touches[0].pageX - event.touches[0].target.offsetLeft)) - canvas_width/2;
		pos_y = (Math.round(event.touches[0].pageY - event.touches[0].target.offsetTop)) - canvas_height/2;
	}
	
	return {x:pos_x, y:pos_y}
}
function mouse_down()
{
	if(ws == null)
		return;
	
	event.preventDefault();
	
	var pos = process_event(event);
	
	var delta_x = pos.x - joystick.x;
	var delta_y = pos.y - joystick.y;
	
	var dist = Math.sqrt(delta_x*delta_x + delta_y*delta_y);
	
	if(dist > radius_handle)
		return;
		
	click_state = 1;
	
	var radius = Math.sqrt(pos.x*pos.x + pos.y*pos.y);
	
	if(radius <(range - radius_handle))
	{
		joystick = pos;
		send_data();
		update_view();
	}
}
function mouse_up()
{
	event.preventDefault();
	click_state = 0;
}
function mouse_move()
{
	if(ws == null)
		return;
 
	event.preventDefault();
	
	if(!click_state)
		return;
	
	var pos = process_event(event);
	
	var radius = Math.sqrt(pos.x*pos.x + pos.y*pos.y);
	
	if(radius <(range - radius_handle))
	{
		joystick = pos;
		send_data();
		update_view();
	}
}
window.onload = init;
</script>
</head>

<body>

<p>
<h1>Arduino - Web-based Joystick</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>

Credits

IoT_lover

10 projects • 192 followers

Arduino - Web-Based Joystick

Things used in this project

Hardware components

Story