QRCodes
A QRCode is a two dimensional barcode that stores information in black and white dots and can be digitally scanned using a smartphone or tablet camera. QRCodes can store a large amount of data such as text, URL's and images so they are ideal for tracking and monitoring employees time and attendance, jobs and tasks.
Existing QRCodes can be used for punching in/out as long as they are unique to each employee. See Enrolling Employees using QRCodes.
QRcodes can be created by using this spreadsheet or other QRcode generators such as MyQRCode.
Example of a QRCode: