Published January 8, 2019 © GPL3+

Arduino - Control Step Motor Precisely via Web

Controlling a step motor by rotating a plate on web.

IntermediateFull instructions provided20,567

Things used in this project

Hardware components

Arduino UNO

DIYables USB Cable 2.0 Type A/B for Arduino Uno

PHPoC WiFi Shield 2 for Arduino

PHPoC Stepper Motor Controller

Step Motor

DIYables DC Power Jack Connector

12V power adapter

DIYables Prototype Expansion Board for Arduino Uno

Optional

DIYables Starter Kit

DIYables Arduino Uno Case

Story

Demonstration

If you are new to Arduino, you can get started with Arduino Tutorials for newbie.

How It Works

When user access webpage of PHPoC [WiFi] Shield from a web browser on smartphone or PC, a WebSocket connection will be created between Arduino and web browser. The WebSocket connection allows for the real-time exchange data between web browser and Arduino without reloading webpage.

When user rotates the plate on webpage, the rotated angle will be send to Arduino. Arduino convert angle to the equivalent number of steps, and then move step motor to the equivalent position.

Angle to the Number of Step Calculation

Assumption:

Angle per step: ANGLE_PER_STEP. This value is got from motor specification.
Angle per mirco-step: ANGLE_PER_MICRO_STEP = ANGLE_PER_STEP / MICRO_STEP_MODE

=> the number of micro-step = angle / ANGLE_PER_MICRO_STEP

The motor I used: ANGLE_PER_STEP = 1.8

The mocro-stepping mode I used in this code : MICRO_STEP_MODE = 32

Wiring

Stack PHPoC Shield or PHPoC WiFi Shield on Arduino
Stack Stepper Motor Controller PES-2604 on PHPoC Shield or PHPoC WiFi Shield
Connect stepper motor to terminal block of Stepper Motor Controller PES-2605
Bipolar stepper motor

Unipolar stepper motor: there are two ways to connect a unipolar stepper motor to terminal block of PES-2605. User can choose one of them.

Source Code

Arduino Code

See code section

Web User Interface - remote_rotate.php

remote_rotate.php is a file that contains web user interface. It needs to be stored on PHPoC [WiFi] Shield. In order to upload the file to PHPoC [WiFi] Shield, please do the following steps:

Copy the below code and save it into remote_rotate.php file.
Install PHPoC Debugger
Connect PHPoC to PHPoC [WiFi] Shield via micro-USB cable according to this instruction.Note that Arduino must be powered.
Upload remote_rotate.php file to PHPoC [WiFi] Shield according to this instruction

The image used in web user interface

step_plate.png

The image also needs to be uploaded to PHPoC [WiFi] Shield

How To

Config network information for PHPoC shield or PHPoC WiFi shield
Install PHPoC Library
Install PHPoC Expansion Library
Compile and upload code to Arduino
Upload web user interface to PHPoC [WiFi] shield
Open Serial monitor and copy IP address of PHPoC Shield
Access web user interface via web browser: http://ip_address_of_shield/remote_rotate.php
Control step motor via web

To buy electronic components, you can order them from utsource.net

The Best Arduino Starter Kit for Beginner

See The Best Arduino Kit for Beginners

Function References

Code

#include <Phpoc.h>
#include <PhpocExpansion.h>

#define CMD_GET	0
#define CMD_SET	1
#define SPEED_LOW_LIMIT		32
#define SPEED_HIGH_LIMIT	100000
#define MICRO_STEP_MODE	32
#define ANGLE_PER_STEP	1.8 // 1.8 degree per full step
#define ANGLE_PER_MICRO_STEP	(ANGLE_PER_STEP / MICRO_STEP_MODE)

PhpocServer server(80);
ExpansionStepper step(1);

unsigned long previousMillis;

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

	Phpoc.begin(PF_LOG_SPI | PF_LOG_NET);
	server.beginWebSocket("remote_rotate");

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

	Expansion.begin();

	step.setMode(MICRO_STEP_MODE);
	step.setAccel(1000000);

	previousMillis = millis();
}

void loop() {
	PhpocClient client = server.available();

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

		if(data) {
			int commaPos, cmd;
			float angle;

			commaPos = data.indexOf(',');
			cmd = data.substring(0, commaPos).toInt();
			angle = -(data.substring(commaPos + 1).toFloat());

			if(cmd == CMD_GET) {
				// send current angle to web
				char wbuf[10];
				long pos = step.getPosition();
				angle = -(float)pos * ANGLE_PER_MICRO_STEP;

				String angleStr = String(angle);
				
				angleStr.toCharArray(wbuf, angleStr.length() + 1);
				server.write(wbuf, angleStr.length());
			} else if(cmd == CMD_SET) {
				long pos, stepNum;

				pos = (long)(angle / ANGLE_PER_MICRO_STEP);

				stepNum = pos - step.getPosition();

				if(stepNum) {
					unsigned long duration_ms;
					long speed;

					duration_ms = millis() - previousMillis;
					previousMillis = millis();

					speed = (long)abs((double)stepNum / duration_ms * 1000.0);
					speed = speed * 8 / 10;

					if(speed < SPEED_LOW_LIMIT)
						speed = SPEED_LOW_LIMIT;
					else
					if(speed > SPEED_HIGH_LIMIT)
						speed = SPEED_HIGH_LIMIT;

					//step.setSpeed(speed);
					//step.stepGoto(pos);
					step.command(F("goto %ld %ld"), pos, speed);

					Serial.print(F("Go to: "));
					Serial.println(pos);
				}
			}
		}
	}
}

<!DOCTYPE html>
<html>
<head>
<title>PHPoC / <?echo system("uname -i")?></title>
<meta name="viewport" content="width=device-width, initial-scale=0.7">
<style>
body { text-align: center; background-color: whiite;}
canvas { background-color: white; }
</style>
<script>
var CMD_GET = 0;
var CMD_SET = 1;
var MIN_TOUCH_RADIUS = 20;
var MAX_TOUCH_RADIUS = 200;
var CANVAS_WIDTH = 400, CANVAS_HEIGHT = 400;
var PIVOT_X = 200, PIVOT_Y = 200;
var plate_img = new Image();
var plate_angle = 0;
var click_state = 0;
var last_angle_pos = 0;
var mouse_xyra = {x:0, y:0, r:0.0, a:0.0};
var ws;

plate_img.src = "step_plate.png";

function init()
{
	var stepper = document.getElementById("stepper");

	stepper.width = CANVAS_WIDTH;
	stepper.height = CANVAS_HEIGHT;

	stepper.addEventListener("touchstart", mouse_down);
	stepper.addEventListener("touchend", mouse_up);
	stepper.addEventListener("touchmove", mouse_move);
	stepper.addEventListener("mousedown", mouse_down);
	stepper.addEventListener("mouseup", mouse_up);
	stepper.addEventListener("mousemove", mouse_move);

	var ctx = stepper.getContext("2d");

	ctx.translate(PIVOT_X, PIVOT_Y);

	//rotate_plate(0);

	ws = new WebSocket("ws://<?echo _SERVER("HTTP_HOST")?>/remote_rotate", "text.phpoc");
	document.getElementById("ws_state").innerHTML = "CONNECTING";

	ws.onopen  = ws_onopen;
	ws.onclose = function(){ document.getElementById("ws_state").innerHTML = "CLOSED"};
	ws.onerror = function(){ alert("websocket error " + this.url) };
	ws.onmessage = ws_onmessage;
}
function ws_onmessage(e_msg)
{
	e_msg = e_msg || window.event; // MessageEvent

	plate_angle = Number(e_msg.data);

	rotate_plate(plate_angle);
}
function ws_onopen() {
	document.getElementById("ws_state").innerHTML = "OPEN" 
	
	setTimeout(function() {
		ws.send(CMD_GET + ",0\r\n");
	}, 50);
}
function rotate_plate(angle)
{
	var stepper = document.getElementById("stepper");
	var ctx = stepper.getContext("2d");

	ctx.clearRect(-PIVOT_X, -PIVOT_Y, CANVAS_WIDTH, CANVAS_HEIGHT);
	ctx.rotate(-angle / 180 * Math.PI);

	ctx.drawImage(plate_img, -PIVOT_X, -PIVOT_Y, CANVAS_WIDTH, CANVAS_HEIGHT);

	ctx.rotate(angle / 180 * Math.PI);

	debug = document.getElementById("debug");
	debug.innerHTML = plate_angle.toFixed(1);
}
function check_update_xyra(event, mouse_xyra)
{
	var x, y, r, a;
	var min_r, max_r, width;

	if(event.touches)
	{
		var touches = event.touches;

		x = (touches[0].pageX - touches[0].target.offsetLeft) - PIVOT_X;
		y = PIVOT_Y - (touches[0].pageY - touches[0].target.offsetTop);
	}
	else
	{
		x = event.offsetX - PIVOT_X;
		y = PIVOT_Y - event.offsetY;
	}

	/* cartesian to polar coordinate conversion */
	r = Math.sqrt(x * x + y * y);
	a = Math.atan2(y, x);

	mouse_xyra.x = x;
	mouse_xyra.y = y;
	mouse_xyra.r = r;
	mouse_xyra.a = a;

	if((r >= MIN_TOUCH_RADIUS) && (r <= MAX_TOUCH_RADIUS))
		return true;
	else
		return false;
}
function mouse_down()
{
	if(event.touches && (event.touches.length > 1))
		click_state = event.touches.length;

	if(click_state > 1)
		return;

	if(check_update_xyra(event, mouse_xyra))
	{
		click_state = 1;
		last_angle_pos = mouse_xyra.a / Math.PI * 180.0;
	}
}
function mouse_up()
{
	click_state = 0;
}
function mouse_move()
{
	var angle_pos, angle_offset;

	if(event.touches && (event.touches.length > 1))
		click_state = event.touches.length;

	if(click_state > 1)
		return;

	if(!click_state)
		return;

	if(!check_update_xyra(event, mouse_xyra))
	{
		click_state = 0;
		return;
	}

	angle_pos = mouse_xyra.a / Math.PI * 180.0;

	if(angle_pos < 0.0)
		angle_pos = angle_pos + 360.0;

	angle_offset = angle_pos - last_angle_pos;
	last_angle_pos = angle_pos;

	if(angle_offset > 180.0)
		angle_offset = -360.0 + angle_offset;
	else
	if(angle_offset < -180.0)
		angle_offset = 360 + angle_offset;

	plate_angle += angle_offset;

	rotate_plate(plate_angle);

	if(ws.readyState == 1)
		ws.send(CMD_SET + "," + plate_angle.toFixed(4) + "\r\n");

	event.preventDefault();
}
window.onload = init;
</script>
</head>

<body>

<h2>
Smart Expansion / Stepper Rotate<br>
<br>

<canvas id="stepper"></canvas>

<p>
WebSocket : <span id="ws_state">null</span><br>
Angle : <span id="debug">0</span>
</p>
</h2>

</body>
</html>

Credits

IoT_lover

10 projects • 190 followers

Arduino - Control Step Motor Precisely via Web

Things used in this project

Hardware components

Story

Demonstration

How It Works

Wiring

Source Code

How To

The Best Arduino Starter Kit for Beginner

Function References

Schematics

arduino_web_step_hardware_NyXyk1dlCv.jpg

Code

Arduino Code

Web User Interface

Credits

IoT_lover

Comments

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Arduino - Control Step Motor Precisely via Web

Arduino - Control Step Motor Precisely via Web

Things used in this project

Hardware components

Story

Demonstration

How It Works

Wiring

Source Code

How To

The Best Arduino Starter Kit for Beginner

Function References

Schematics

arduino_web_step_hardware_NyXyk1dlCv.jpg

Code

Arduino Code

Web User Interface

Credits

IoT_lover

Comments

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