Make Your Own GRBL CNC Pendant




Introduction: Make Your Own GRBL CNC Pendant

So you just finished your DIY CNC machine, set up GRBL and even cut your first part.  Now what?  Well, did you know that as of GRBL v0.8 there are pinouts some really useful commands such as Cycle Start, Feed Hold and a Soft Reset?  Cycle Start and Feed Hold allow you to literally pause your machine so you can double check that your tool isn't about to hit a clamp, or maybe you just need to run inside to grab some more pizza.  Once you get back, just hit the Cycle Start button and BAM! your machine goes on its merry way as if nothing had ever happened....

Although these commands are accessible via the terminal, I decided that I really wanted to have a nice pendant with easy to use buttons - and maybe a few extra buttons for future development!  So grab your soldering iron and lets get to work!

Step 1: Components

There are a few components that we need to complete this project, I set up a handy-dandy wishlist over at Sparkfun with *most* of the parts, the rest you will have to source yourself.

What You Need:
- Soldering Iron/Supplies
- 10 wire Ribbon Cable
- (2) serial port connectors (one male, one female)
- serial cable
- (3) arcade machine buttons.  I like Green, Yellow and Blue
- (2) switches
- Mushroom style E-Stop button (Mine came from
- Screw terminal block (I don't recommend the white, "European Style" blocks because they don't work well with small wires)
- Aluminum Enclosure
- Drill press with Step Drill (Amazon has step drills for $cheap$)

Here is a link to my Sparkfun wishlist:

Step 2: Plan

Before digging into a project, it is good to figure out a plan.  I did a quick little MSpaint sketch to show how I wanted my button layout and my wiring set up.  Basically, my Cycle Start, Feed Hold, Reset, and E-Stop buttons will share the Arduino Ground (-) wire.  The two switches will be on their own circuit since I don't really know what I want to use them for.  Everything will tie into my terminal block before exiting via the serial connector. There are probably better connectors than a serial connector, but Sparkfun had some cool little plugs and they were cheaper than other options that I found. 

If you are interested in the GRBL pinout for other projects, check out this link:

Once I figured out where I wanted everything, I used my step drill to drill some some big holes. 1-1/4" to be exact, my drill press really struggled, so be careful!  Once the holes were drilled, I tested the fit of the buttons (to make sure they were not too tall) and checked the location of my terminal block.  When I was sure that everything was in a good place, I glued in the terminal block and went to soldering....

Step 3: Soldering

Carefully start soldering the buttons together, be sure to double and triple check your diagram!  Write lots of notes about what wires go to what pins on the serial connector.  If you solder the wrong pin, it can be tough to figure out why your pendant isn't working.  Once everything is hooked up, carefully close the box.  I had to wiggle stuff around to get it to fit correctly and had a lot of trouble with wires escaping the terminal block.

Step 4: DONE!

Before connecting to your machine, I recommend using a multimeter to double check that your buttons match the pins that you wanted to use.  This will save a little bit of time before you put you machine back together.  If everything is set up, you should be good to go!

I hope you found this Instructable useful, unfortunately I wasn't planning on doing a writeup when I made the box - thus the lack of pictures.  Good luck and happy GRBLing!

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    3 Discussions

    Poppy Ann
    Poppy Ann

    5 years ago on Step 3

    Hi there,

    First a great instructable well done.

    Second you state that you had a lot of trouble with wires escaping the terminal block, were you just inserting the wire inside of the plastic insulator or both the wire and plastic insulator.

    with this type of terminal block you need to either

    1. Bend the wire over the plastic coating and insert it with the wire down and the plastic up towards the screw so when tightened the screw grips the plastic pushing the wire into contact with the metal connector as this way you get the mechanical strength of the plastic coating along with the interior wire.

    2. Fit a bootlace terminal to the end of the wire and then use the terminal in the connector.

    3. Tin (solder) the end of the wire to hold the strands together then push the tinned end in the terminal and tighten the screw.

    just using the little individual wire strands to hold the wire in the connector is asking for trouble as when you tighten the screw lots of the little wires get cut in half and you end up with only a few little wires trying to hold the wire into the terminal.


    7 years ago on Introduction

    just curious, what do you have the two top switches wired to? spindle? great work on the pendant, on my to-do list now....


    Reply 5 years ago on Introduction

    Blower and work light. I was curious too, he annotated the picture. :)