You will need
- DK weight wool yarn with gauge 20-22sts/10cm(4”) (eg. Sandnes Smart Superwash). This is a perfect chance to use leftover yarns.
- Crochet hook 4mm (or size to obtain gauge)
- Tapestry needle
1. Create the QR code pattern
Turn your website address into a QR code using a code generator, for example Kaywa QR code.
Save the generated QR code image and open it in your image editing application (for example PhotoShop). Scale the image size down to 31x31px. Make sure that the image stays black and white – if shades of grey appear in the scaling process, you may have to do some color replacing. Save the image as png.
Use knitPro web app to turn your QR code into a crochet pattern. Upload your image there and it produces you a graph where 1px = 1 stitch. You will get a 31×31 stitch grid.
2. Crochet the piece
1 horizontal stitch in the pattern is 2 dc in the crochet. 1 vertical stitch in the pattern is 1 row of dc in the crochet. There is 64 dc in the work altogether (62 in the pattern and 1 in each edge for turning).
Chain 66. 1 dc into 3rd ch from the hook, continue to the end of the row (3ch + 63dc altogether). Turn the work. 3 ch (the first dc of the row is always 3 ch), continue with dc.
Crochet the piece using any colors you like. Note that in order to create a working QR code you have to keep the contrast between the foreground and the background colors relatively high. Read more instructions in the ShareSquare article How not to screw up your QR code part 1: contrast – they have found out that the contrast ratio has to be at least 4:1. You can count the ratio between any two colors using Juicy Studio’s Contrast ratio calculator.
Weave in yarn ends. Block the piece: smooth it a bit until it is in a square shape and pin it onto a surface that can handle moist (for example a thick towel). Moisten the piece with cold water using a spraying bottle and leave to dry.