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MSP430F4270 Altimeter Demo

INSATien
Prodigy 110 points
Other Parts Discussed in Thread: MSP430F4270, MSP430FR5739, MSP-EXP430FR5739

Hi,

I am building my own altimeter demo using the pressure sensor MPX2102A and I didn't succed to have a good precision.

In fact, when I left the sensor at table (constant pressure) I get a variation of ~1.7 mB which is not acceptable for altimeter application.

Does anyone tested the "MSP430F4270 Altimeter Demo" and faced such issue?

As an exmple, on 210 samples I found that the minimum pressure is 1118.1724  mB and the max pressure is 1119.8996  mB !

I thought to have a constant pressure with precision ~ 0.1mB, is that achievable?

 

Thanks & Regards,

  • 0
    TI__Genius 10830 points

    Is the variation you observe before or after averaging?

    "In this demo application, averaging techniques are used to filter out noise and stabilize the conversion result that is used for the math calculations."

    Reference: MSP430F4270 Altimeter Demo (PDF 1041 KB) 30 Jun 2005

  • 0 in reply to Jason Work
    Prodigy 110 points

    Hi jason,

     

    I am observing variation after averaging and even if I change the averaging to 100 sampes I get pressure changes about 1.7 mB which doesn't fit the requirement for altitude measurement.

     

  • 0 in reply to INSATien
    TI__Genius 10830 points

    MSP430F4270 Altimeter Demo was published in 2005.  If I was going to make an altimeter application now, I would probably start with a Bosch BMP180 rated for +/- 1 m accuracy.  Since it uses I2C, this removes the constraint of using a sigma-delta ADC.   In that case, the MSP430FR5739 on the MSP-EXP430FR5739 might be a good MCU selection to build a prototype on.  Making a simple BoosterPack could power the sensor (SV1 pin 12 and SV2 pin 12), and provides access to the I2C (SVC 2 pins 1 and 2).  The FRAM could easily log the pressure data.

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