A customer requested a web application which allows to scan QR codes on invitations. It should run on mobile phones. The validity check is performed within a Navision system via a SOAP webservice. The most important requirement was a high-performant interface, because the customer has events with several thousands of guests.
I was first sceptical about the performance of the internal mobile phone cameras and the scan speed, so I recommended a hardware solution, connecting a professional QR code scanner to a mobile phone with an OTG adapter. We experimented a bit and found that the internal camera is completely sufficient if it is used together with a fast QR scan app.
Which apps are good for this application? We tried "Niko Barcode Keyboard" free and premium, and "Keyboard with Barcode/NFC Scanner" from TEC-IT. All three are perfectly usable for this case. The premium Niko Keyboard has a feature of a numeric keyboard on which the QR scan button is very large. This is a nice feature usability-wise. The TEC-IT scanner is a little bit faster though. It is so greedy that it even finds QR codes in the surroundings which were not meant to be scanned.