AYABInterface – a Python Module for the AYAB shield

In the Google Summer of Code effort on knitting machines with AYAB, we created the AYABInterface module. This module allows us to control machines like the Brother KH-910. Click here to see it in action.

The development process for small changes worked like this:

  1. Talk about uncertainty in the issue.
  2. Write the specification.
  3. Write the tests.
  4. Write the code.

Of cause these steps were mixed but the objective is clear to first specify and then let the implementation follow.

From my perspective this made sure that other people can implement this protocol, too. After all, it should be specific enough now, to write source code for it.

The underlying Communication relies on a byte stream to communicate. This abstracts from the serial protocol and enables us to plug in e.g. sockets if someone wants to communicate via WIFI or LAN.

The communication walks through several states. They are documented in the states module. Here you can see an overview over the different states:


If you click it, you are redirected to an interactive documentation web page where you can click the different states and messages to view their implementation.


After all, communication is important, not only between the shield and the computer but also for the developers. Since the Shield is around for a while, this protocol is now documented in a way that allows us to use it also for other applications. A specification driven implementation allows us both:

  • a complete specification where we know what is possible to implement
  • an implementation that follows the specification and as such is exchangeable and a reference for other library developers.


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Introduction of the 2016 GSoC projects with AYAB

Hi, we are Kirstin and Nicco and for the next couple of months we will be working on the AYAB project. AYAB is an abbreviation for All Yarns Are Beautiful and the project works on the Software that interfaces with the knitting machine and directs in in what to knit. Zou can read more about the existing software in the recent blogposts.
We want to implement two new features and expand on the functionality of the software that replaces the original firmware of the knitting machine.

We want to work on an exchangeable format that stores all information necessary for knitting e.g. a sweatshirt. It should contain the sewing pattern, the color pattern(s) defined for the different parts of the knit piece and the stitch pattern, also defined for the different parts of the knit piece.

This new information that we will have through the format will allow us to create directions for the user in case the machine cannot switch yarn colors on its own or add or remove stitches, but the user can. We want the software to have on screen instructions for the user, telling the user what to do before they knit the next row. This will make knitting with more than two yarn colors possible and make it easier for users to knit shapes where they need to add and remove stitches. This is very much needed when knitting clothes.

Our next steps are to make user studies to find out about how people use the knitting machines, what is necessary and important. If you like to lend us a hand, please contact us. Also we are doing weekly hangouts in the evening, Tuesday 21:00 (Berlin, GMT+2).

Continue ReadingIntroduction of the 2016 GSoC projects with AYAB