Is there an app that allows your Android device to act as a barcode reader, in such a way that it can send something like keyboard inputs to a computer in real-time?
I use Kinoni Barcode Reader Pro.
A lot of other "Send Barcode to PC" Apps require you to manually setup and configure the server part on your the PC (mostly VNC) that receives the barcode.
With this one, you just install the App, download their PC Setup Program and make sure that your phone is connected to the same network as your PC.
That's it. Although it costs 5€, you are done in no time and it simply works.