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[on:]

I played around with a Bosch Sensortec BMP085 pressure sensor a while ago.  It has a digital output, not analog.
The datasheet claims a noise level of 0.03 hPa (standard deviation of 10 readings) in the "ultra high resolution mode".

My experiments with two of these units in the same sealed jar, with very slowly changing temperature, showed a p-p noise level around 0.15 hPa and the two sensor readings differed by about 0.35 hPa, giving me a feeling for the accuracy that might be achieved.  Can anyone suggest a (small, inexpensive) pressure sensor which does better than this (lower noise)?

Here are some graphs and data from the BMP085:
http://jeelabs.net/projects/cafe/wiki/Pressure_Plug_measurements

[Reply #1 on:]

What is the range you need?
What is the accuracy?
Can you tell something about the environment the sensor has to operate in??

Can you tell something about the goal of your project?

[Reply #2 on:]

Let's say a weather-station type application: normal atmospheric pressure at sea level, +/- normal barometric pressure variability (1010 hPa +/- 50, and typical room temperatures (eg. 18 C -> 30 C).  I'm just curious about what is available.

I know there are microbarometers which achieve very high resolution but they are usually large with an external pressure reference chamber that must be kept thermally isolated.  Maybe what I'm looking for is a compact microbarometer.  And inexpensive, if possible :-)

[Reply #3 on:]

a quick google - http://www.mulder-hardenberg.com/en/industrialautomation/data_loggers/sensors/documenten/Hobo_Sensors.pdf -

its industrial stuff so probably expensive

- http://www.sparkfun.com/products/9602 -  (they have this ones besides the BMP085)
DATASHEET: - http://www.sparkfun.com/datasheets/Sensors/Pressure/MPL115A1.pdf -

reading the comments brings me to

- http://www.futureelectronics.com/en/technologies/development-tools/analog-power/Pages/8762254-KITMPL115A1SPI.aspx -
which is a workable breakout box: guess it will be between $15-$20 (no promise

MPL115A1 Featuers:

    Digitized pressure and temperature information together with programmed calibration coefficients for host micro use.
    Factory Calibrated
    50 kPa to 115 kPa Absolute Pressure
    1 kPa Accuracy
    2.375 V to 5.5 V Supply
    Integrated ADC
    SPI Interface
    Monotonic Pressure and Temperature Data Outputs
    Surface Mount RoHS Compliant Package

Just googling helps ...

[Reply #4 on:]

Go with the MS5611-01BA. Small, light and extremely precise.

I can share with you an arduino library for it and a libre breakout board desing.