DIY Scanning Vibrometer


2008-01-08 11:51 pm
Scanning laser tape measure. Yes, can do this, if somebody funds it. Not dissimilar to a scanning nearfield antenna analyser. Or a scanning anything for that matter. Can probably get away with a dismantled plotter. Or maybe a Sherline CNC mill with a rotary table. Only a couple thousand $$ for the mill. Excite, move, measure, move, measure, move, measure, might be a few little issues... something about a triangulating laser. Predict the SPL at a point r(ro,φ, θ)from the Rayleigh equation? What's the incentive?

Ha, you had me going for a second. I've used the optical vibrometers from PI and thought if you can clone one of those, you're a better man than I. The system described shouldn't be hard to do using commercial or DIY XYZ platforms, though I'm not sure an individual constructor could benefit much from the information. It seems best suited to those building drivers from scratch.


2007-10-09 7:30 pm
I have worked with those laser doppler vibrometer. nice stuff, but expensive.
here's another idea: use laser triangulation, take the optics from a sharp displacement sensor, build a fast readout and use a CODEC with CPLD to do the A/D , division and D/A.
we can use a fast PSD from hamamatsu, sharp, or pacific optics. we do not have the obligation to measure from a distance so triangulation is an option. linearity is OK and resolution can be in the um range.