Most phone cameras with QR code scanning capabilities can handle the following examples encoded. I used the following code to make these: require "rqrcode"
data = "the data"
qrcode = RQRCode::QRCode.new(data)
png = qrcode.as_png(
bit_depth: 1,
border_modules: 1,
color_mode: ChunkyPNG::COLOR_GRAYSCALE,
color: "black",
file: nil,
fill: "white"…