I'm working with a friend to provide instrumentation for a coke-can Stirling engine he's building (the kind you can see on Youtube).
As part of this, we'd like to measure revolutions per second of the flywheel and the pressure on the balloon diagram. RPM of the flywheel is pretty easy to calculate with an optical encoder but I've no idea how to go about measuring pressure of the vessel.
I'm not sure if there are any sensors capable of detecting the presumably small changes in the pressure in the system. Similarly the flywheel is capable of reaching 900RPM +/- 1%, thus the "system frequency" would be about 900/60 = 15Hz so my sampling frequency would want to be at least 30Hz and probably well oversampled (100-200Hz?) so I can plot this over time.
In summary, can anyone recommend a sensor capable of detecting very slight changes in pressure at a rate of at least 30samples/second?
Best Answer
I would use one of the Freescale sensors MPXV7002 http://uk.farnell.com/freescale-semiconductor/mpxv7002dp/sensor-pressure-dual-diff-0-02bar/dp/2080499
It says the response is 1.0 ms
However as @Nick Alexeev says... you need to know the expected pressure because I think you will break this one. On the plus side they do offer sensors for different ranges.