cnc-pi

CNC Controller for Raspberry Pi, using NodeJS

Here is a YouTube video showing what it looks like:

Table of contents

• "It works on my machine"
• Setup
• Dependency
• What's inside
  • MotorController.js
  • CNCController.js
  • server.js
• Example project using 2 CD/DVD drives (coming soon)

"It works on my machine"

I only tested this on a Raspberry Pi 2 Model B with this setup:

• Linux Raspbian 4.9
• NodeJS 9.8.0

Setup

At the root of the project, run:

npm install

Dependency

This project requires the rpi-gpio npm module.

What's inside

Inside the controllers folder, you'll find two modules:

• MotorController.js
• CNCController.js

At the root, you'll also find a server.js which uses Express and provides a web interface to draw stuff and send it to the CNC machine (more info below).

MotorController.js

This modules acts as an abstraction layer for DC motors and stepper motors using Raspberry Pi GPIOs. It's a function which returns an instance of a motor. You need to pass an options Object to it.

Options

Option	Type	Mandatory	Example value	Description
pins	Array	yes	[15, 11, 13, 12]	A list of GPIO pin numbers (3 for DC motors, 4 for stepper motors)
gpio	rpi-gpio object	yes	-	A reference to rpi-gpio
type	String	no	"stepper"	Type of motor: "stepper" or "dc" (default)
delay	Integer	no	5	Delay between each step (in milliseconds, 5 by default)
name	String	no	"myMotor"	Name of the motor, for debugging purposes
logs	Boolean	no	false	Whether or not to enable logs (true by default)

Methods

• init() Checks parameters and sets every GPIO pin to DIR_OUT mode.
• forward(steps) Rotates the motor in forward direction for a given number of steps.
• backward(steps) Rotates the motor in backward direction for a given number of steps.

Example usage

const gpio = require('rpi-gpio');
const Motor = require('./MotorController.js');
// Define the motor
const myMotor = Motor({
	pins: [15, 11, 13, 12],
	gpio: gpio,
	type: 'stepper',
	delay: 5,
	name: 'myMotor',
	logs: 'true'
});

// Initialize it and make it turn
myMotor.init()
.then(m => m.forward(20))
.then(m => m.backward(20));

CNCController.js

This modules acts as an abstraction layer for a CNC machine. It uses the MotorController module to create 3 motor instances (x, y, z) and control them in the 3D space. It's a function which returns an instance of a CNC machine. You need to pass an options Object to it.

Options

Option	Type	Mandatory	Example value	Description
x	Object	yes	See above	A set of options to pass to the MotorController for motor X
y	Object	yes	See above	A set of options to pass to the MotorController for motor Y
z	Object	yes	See above	A set of options to pass to the MotorController for motor Z
name	String	no	"myMotor"	Name of the motor, for debugging purposes
logs	Boolean	no	false	Whether or not to enable logs

Methods

• init() Checks parameters and initializes every motor.
• move(positions) Moves the CNC to the given coordinates. The positions parameter should be an Array of integer positions for each motor (e.g. [5, 10, 0])
• trace(path) Traces a series of straight lines in the 3D space. The path parameter should be an Array of positions (e.g. [[0, 0, 0], [5, 10, 0]])

Example usage

const gpio = require('rpi-gpio');
const CNC = require('./CNCController.js');
// Define the CNC
const myCnc = CNC({
	name: 'myCnc',
	x: {
		pins: [15, 11, 13, 12],
		delay: 5,
		type: 'stepper',
		gpio: gpio
	},
	y: {
		pins: [37, 33, 35, 31],
		delay: 5,
		type: 'stepper',
		gpio: gpio
	},
	z: {
		pins: [18, 16, 22],
		delay: 10,
		type: 'dc',
		gpio: gpio
	}
});

// Initialize it and make it draw a path
myCnc.init()
.then(c => c.trace([[0, 0, 0], [5, 10, 0]]));

server.js

This script starts a server on http://localhost:3000. It exposes a simple HTML page where you can draw on a canvas, and send the data to the CNC machine.

Make sure you set the correct parameters for your motors and pins, and you should be good to go!

Example project using 2 CD/DVD drives

Tutorial coming soon