The comments are enthusiastic mostly and here is one from Robert V:

Sweet! If the laser was projected vertically to the bottom of the lens and a front silvered mirror above the lens would allow the sample to be horizontal, great for fluid objects to be projected.

RimstarOrg has this to contribute:

Cool! I have a phototachometer similar to yours but it has a focused lightbulb instead of a laser. A trip to the dollar store is in order. Thanks for showing us this

It is this kind of video that will encourage more people to get into science!  You don’t have to be a braniac or have an engineering background to appreciate home science on all levels and svae money when making your devices.  We hope you enjoy the video.