Hello there ,
I was using the QR generator you mentioned on your page here: using-qr-codes-in-stockd-v1.4.
I really enjoyed working with phpqrcode.sourceforge.net in the past, but I recently found a new one that is more visually appealing, has a lot of customization options, and is totally free:
It allows you to create your own personalized QR code (you can choose the color, add a frame and even add the logo of your company and/or social networks), which I think is awesome.
I believe that it would be a great addition to your page, I'm sure your readers will appreciate it.