The second attempt at 3D printing a base plate for the πFi went much better but there’s still plenty of room for improvements. Currently I’m testing out sizes for the QR cards and how those sizes effects the necessary distance between the cards and the camera, which in turn effects how large the whole device will need to be. Currently I’m leaning toward a 7,0×8,5 cm large card with a 5,5×5,5 cm QR code centered on the card and this means that the full enclosure doesn’t need to be any bigger in the base than the Pi itself is.
If stand for the QR cards are on top of the USB och Ethernet ports with just a couple of mm of plastic between them, the camera sensor need to be about 55 mm above the surface of the Pi.
If I connect a display to the Pi I can use
raspivid to display the output of the camera on that display. The display needs to be connected to the Pi but the command itself can be run either locally on the Pi or remotely via SSH.
raspivid -o video.h264 -t 180000 -w 640 -h 480 will display an image for three minutes, showing the same that the QR Reader script will see.