Where to start prototyping with straingauges?
Can anyone recommend a reasonably-priced prototyping kit for straingauges or something similar, and/or a good document on how to actually design around these beasts?
What I'm trying to build is essentially a box with a handle on each end, which can measure the force applied inward or outward on those ends. Measurement range would probably about +/- 40 pounds, though I'd be happier if it could tolerate (but not necessarily measure) higher forces just in case someone does something stupid. The measurement doesn't have to be on a smooth curve but does need to be continuous and repeatable so I can calibrate it reasonably accurately. If you think of it as a kind of game controller, where you're squeezing it together or pulling it apart to varying degrees to make the game respond, that's fairly close to what I need.
Doesn't necessarily have to be straingauge, but needs to be something with essentially that behavior -- I really want to measure the pressure/tension applied with imperceptable motion (for fast response). And yes, I do need both directions.
Unfortunately all the documentation I've found on straingauges talks about the electronic aspects. and says very little about the practical mechanical aspects of working with them. And I haven't yet seen anything resembling a reasonably priced experimenter's/prototyping kit from any of the manufacturers.
Yeah, I suppose I could cannibalize an electronic scale for the first prototype... but I'd still like to learn the proper approach and find an experimenter-friendly source of parts.