Hacking the Brother KM-950i

“Hack a knitting machine!” They said.
“It’ll be fun!” They said.

Well, I did get there eventually. But it was a battle just to get two-colour hacked knitting working (not of Mordor proportions, but still very big). I’d like to give you a quick introduction of the code and methods I used. I’ll be posting about upgrading to the multi-colour hack (ie, more than two colours) in the coming weeks. Stay tuned!

Back in 2013 when I lived in London I tinkered around with a Brother KM-950i knitting machine at the London Hackspace. Thanks to the awesome work by Adafruit there was a python hack available for the Brother KM-930e so I thought I could just dive in and make my own hacked knitting.

Cue proverbial rabbit hole.

Hacking a knitting machine involves talking to it using a modern day computer to upload and download knitting patterns from simple bitmap images. Think of it like turning a knitting machine into a printer. A very wooly printer.

While the Brother KM-930e hack got me 80% of the way to hacking the Brother KM-950i, there were a number of limitations I needed to address. I met the wonderful Sally Kentfield at the Brighton Mini Maker Faire who also hacks a Brother KM-950i but she prefers to use her husband’s GUI written for Windows. I opted to keep working on the command line Python hack as it works on any OS, being a Mac nerd myself. Also, command line > fun 😀

So my version of the Adafruit hack addresses:

  • A rewrite of writeSector to support the 32bit format of the Brother KM-950i (Brother 930e is 16bit).
  • Supply the blank pattern files instead of requiring them to be generated first. Thanks to Charles Yarnold we have the full set.
  • Support png file format.

You can find my code release here. Instructions for how to use it can be found on the Adafruit website.

The other challenge with knitting two-colour is the sheer learning curve with the knitting machine itself. You have to:

  • Find the right yarn – cone yarn 4ply or lower.
  • Setup the machine correctly – hello instruction manual!
  • Choose the right cast on and cast off methods – I cannot recommend Diana Sullivan’s YouTube channel  enough.
  • Choose the right colour technique to suit what you want to make…

Below are the fronts and backs of some sample swatches I made of the London Hackspace logo in four (very different!) knitting methods:

Left to right anti-clockwise: fair isle float pickup, intarsia, double jacquard, latched fair isle

Left to right anti-clockwise: fair isle float pickup, intarsia, double jacquard, latched fair isle

I lean toward double jacquard as my preferred method these days (thanks Sally Kentfield!) for its speed and flexibility, but it’s not an easy method to master. If the machine isn’t oiled and setup perfectly, things go wrong very quickly.

A few geeky scarves I’ve knitted in double jacquard with the 950i hack:

Cellular automata 150 scarf

Dragon curve fractal scarf

Recursively grown tree scarf

 

 

 

 

 

I hope this post helps anyone who’s thinking of doing some hacked knitting of their own. Let me know how you go in the comments below! Enjoy.

Sarah Spencer

I’m the crafty type. I enjoy lead lighting, knitting, crochet, screen printing… the list goes on! I also work in IT so I write code from time to time.

You can find me on Github and Twitter.

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