[mdlug] Capturing USB events for reverse-engineering?

[David McMillan]

     So, I've got this cheap USB microscope that both Windows and Linux 
recognize as a standard webcam.  But it has a button on it to trigger 
taking images, which only works with the Windows-only proprietary 
software that came with the 'scope.  And it occurred to me that 
detecting this button push under Linux and using it to trigger a capture 
probably shouldn't be too hard (this unit is too cheap for the mfgr to 
have spent much effort on anti-hacking measures).  But then I realized 
-- I have no idea how one goes about this kind of thing.  It's just 
never come up in my "Linux life" before.
     So... anyone know a good "idiot's guide" place to start?