Scott Harden has a nice build log on his precision pressure meter project:
I just completed building a device capable of measuring temperature to one hundredth of a degree Celsius and pressure to one ten-thousandth of a PSI! This project is centered around an ICstation MS5611 temperature sensor breakout board which was small enough to fit inside of a plastic syringe. The result is a small and inexpensive pressure sensor in a convenient form factor with a twist connector (a Luer-Lok fitting) that can be rapidly attached to existing tubing setups. Although the screw attachment would work well for industrial or scientific applications, I found that the inner connector (the non-threaded plastic nub with 6% taper) made a snug and air-tight connection with my CO2-impermanent aquarium tubing.
Project info at Scott Harden’s blog.
Check out the video after the break.