Early computer programs were communicated via punch cards, a system that was lifted from the textile industry. You can still use punch cards to operate knitting machines, but a few groups are now bringing the technology full circle by hacking knitting machines so that they may be operated digitally via an Arduino.

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This is a Silver Reed knitting machine that works in a similar way to Brother’s earlier machines; both operate mechanically by punch card. Notice that the zig-zag on the punch card corresponds directly to the zig-zag pattern of the blue and pink yarn on the bottom. Photography by Sophia Smith

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Photo courtesy of AYAB Knitting

The folks at AYAB Knitting developed an open source Arduino shield (shown to the right) that effectively translates a digital input into a mechanical output on the knitting machine’s needle bed. Watch their short video below for the general idea:

If you happen to have a 1980’s Brother KH900 series knitting machine lying around that you’d like to hack, they give rather fabulous and thorough documentation on their website.

AYAB Knitting also provides a quick start video showing how to hook up the shield to the knitting machine. After that, you just download the software, install the Arduino Driver, configure a few settings, and you’re ready to knit yourself a cozy road of textile’d glory.

At Maker Faire Bay Area this year, the Machine Knitters Guild of the San Francisco Bay Area was cranking out a number of designs with the help of their Arduino shields. In addition to demonstrating the work done by AYAB Knitting, they tell us that they “have contributed bug reports, feature suggestions and documentation.”

The MKGSFBA demonstrated a variety of different set-ups, including one machine that is purely mechanical with a punch card (shown above), and another machine which has been gutted and upgraded with an Arduino (shown below), which feeds the knitting pattern directly from a computer to the needle bed.

The system is binaristic, supporting two colors of yarn. A punch on the punch card is a positive value that uses pink yarn, and no punch is a negative value that yields a blue stitch. The machines are capable of knitting any image that’s 200 pixels wide, each of which correspond to one of 200 needles that occupy the needle bed.

Under the hood of MKGSFBA member Adrienne Hunter's hacked knitting machine. Photo by Sophia Smith

Under the hood of MKGSFBA member Adrienne Hunter’s hacked knitting machine.

A sampling of the work knitted by the Machine Knitters Guild of the San Francisco Bay Area. Photo by Sophia Smith

A sampling of the work knitted by the Machine Knitters Guild of the San Francisco Bay Area.

“It’s quite an arm workout,” says Krista Hunter, MKGSFBA member and engineering manager of PAX Labs, as she pushes the carriage back and forth. Maybe their next knitting hack can involve a robotic arm!

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Krista Hunter showed me how the ink smudges of this "Fragile" sticker are preserved when she digitized the design for knitting. Photo by Sophia Smith

Krista Hunter showed me how the ink smudges of this “Fragile” sticker were preserved when she digitized the design for knitting.