Hung up the QR Code at the Entrance. This is quite a great way to record details of customers coming into the shop.
Android: Need to install a QR Code Scanner App.
iPhone: Just turn on the Camera function.
However, this is definitely not user friendly especially to Aunties and Uncles. Most of them think that learning new thing: to use QR Code Scanner is troublesome.
The QR Code Page can be downloaded here: