coding for direction flow.

[salfordbug]

Hi all.
I need a little (a lot) of help.
i have two input sensors (A - mounted about 100mm apart
they are connected to the pc via the velleman k8055 usb card.
what i need to do is detect which sensor is triggered first, so direction can be obtained.
i.e. A triggered then B triggered is left to right or B Triggered then A triggered is right to left.
i`m using vb 2010.

thanks m