Had some time this weekend to tweak the vb.net display. Data points are displayed as bitmaps on a working waterfall display. Further code cleanup is required but it's pretty efficient as is. No more crashes after 250 data points are collected and no more flickering as the bitmaps are handled by the form.paint event.

On other fronts, I'm considering these vibration sensors as my active elements. https://www.sparkfun.com/products/9196 I don't know how well they would work though for this application. I will have to order one and try it.