Picture of 3 Axis Arduino Based CNC Controller
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I've been playing with different CNC designs and Stepper controllers for many years now. I started building CNC machines long ago. My first inspiration came from Bruce Shapiro’s eggbot. I tried a few variations of it and even the board from evil mad scientist. Recently a project named GRBL came along that caught my eye. It used an Arduino to do the G-Code Interpretation. It still outputs step and direction pulses so all my existing designs worked fine with it.

The latest generation controllers I have built all use the same simple and cheap IC's. A pic 12c508 as the basic stepper driver logic and some H-Bridge chips that were originally meant for mundane things like tray loading motors on dvd players. I got a couple of hundred of these on ebay. The pic micros were from a guy that used to do mod chips with them but sold out his stock of unused chips really cheap.

I've used the cheapest parts I could find and still got great results with modest fine tuning. I used a dial indicator to see how bad my table was and it only varied .008 inches in depth from end to end. If I had used a surface planed board or aluminum plate that would have been better. I could always just mill a huge squared spiral pattern into the table to make it perfect

Step 1: Single Board or Multiple Board Modules

Picture of Single Board or Multiple Board Modules
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I've tried both ways and each has its advantages. I always keep the 110V SSR board separate. When using the single board approach I like to use an Arduino nano clone. when using multiple boards I use and arduino prototype sheild wired with a bunch of headers for the individual boards.

Invento Guy14 days ago

your idea of making this cnc machine is awesome..!

But you haven't provided full circuit diagram with arduino and its code..!

in your other instructable you have provided circuit of stepper motor controller ,but not cnc controller circuit..!

please send me the full circuit with code "maheshjshetty@gmail.com"

blackboy_jakk9 months ago

Are you use stepper motor driver?
And I want blueprint of circuit board,Can you show?

rjkorn (author)  blackboy_jakk4 months ago

I used H-bridge drivers because that's what I had on hand. I did another instructable about them here:


I hand-wired the protoboard by following the hookup diagram in the GRBL wiki. I never bothered to document the board since I figured everyone would have a unique take on how to assemble a cnc and make it their own.

I have since moved on from GRBL in favor of a controller that does ARC's and has a few more options.

raoul.ursum4 months ago

Where is the code for the arduino and the schematic of the electronics? Could you also tell me which programs you will need to get it working? And last I want to draw in AutoCAD the things I want to mill out. Could that work?

rjkorn (author)  raoul.ursum4 months ago

The code for the arduino is on the GRBL project github, its been updated a couple of times since this was published.

there is also a hookup diagram in their wiki that I followed. I did use a couple of custom pics to drive the H-bridge chips I had lying around. if you're interested in it that code is in this instructable


steelspark1 year ago
Inventables sells a aurduino g-sheild that fits right on top of the aurduino and will control a 3-axis cnc if that helps anyone. It is what I use.
rjkorn (author)  steelspark1 year ago

Yeah I looked at a lot of those but many use the little stepstick driver chips. they like to overheat. These big SIP's easily transfer heat out. I've run the thing for 7-8 hours straight and the heat sink barely got warm. I could leave my hand on it comfortably. I wanted to do some long jobs. I guess it a matter of your intended use. My next big job is a Gallifreyan plaque for my sister. it might be the longest one yet but I wont have to worry about overheating the controller. I added an Air jet to keep the bit cool too.

prophead1 year ago
Great job with the details and explanations. It's answers many questions and makes a terrific roadmap for anyone trying to learn.