Hello! Before start giving answers I need some info: how many users needs to be tracked?
OS (mac, gnu/linux distro, windows)?
Preferred stack (node+gulp+browserify, node+grunt+wellIthinkYouGotThePoint)
I recently played with barcodes for an store app, the barcode get printed with a Dymo printer (but whatever printer can do the job), then in the shop the cashier read them with a barcode scanner (around 14$ on amazon) and place the order.
With nodejs, I used this library for generating the barcode: http://lindell.me/JsBarcode/
For reading them instead, is dead simple: those barcode scanners simply read the code and send it to the PC "emulating" the keyboard: is like you typed the code by yourself, with an extra "end of line" character (usually \n but some use \r\n)