Thanks for the recommendation, FvM, I've looked into piezo transducers as an alternative to accelerometers, and they seem very promising, at least on paper. I've tested a few I had laying around, but unfortunately the performance seems to very greatly. None of them have any type numbers on them, which makes it difficult to replicate results.
Can you recommend type numbers or manufacturers of piezo transducers you have good experiences with? I have found Cui Inc. discs being widely recommended, so you share that experience?