NAVIO: Measuring pressure and temperature with MS5611 [C++, Python]

MS5611

This document is not updated, please proceed to docs.emlid.com for latest version!

MS5611 is the best in class barometric pressure sensor, it has built-in temperature sensor for calibration and can determine altitude with 10cm resolution. It is very important to protect MS5611 from direct sunlight and air streams as these factors can significantly lower accuracy of the sensor and cause sudden jumps in measurements.

[C++]

MS5611 example

Move to the folder with the source code, compile and run the example

cd Navio/C++/Examples/Barometer
make
sudo ./Barometer

You should see pressure and temperature values. Keep in mind that board tends to get hot from Raspberry and would show slightly higher temperature than it is in your room.

MS5611 code

Here is the main code, which is mostly self-explanatory. As it takes some time for the sensor to perform conversion delays are added between calls to methods that start the conversion and read the resulting data. After reading both pressure and temperature values temperature compensation can be performed to get resulting pressure value.

#include "Navio/MS5611.h"

int main()
{
    MS5611 baro(RASPBERRY_PI_MODEL_B_I2C, MS5611_DEFAULT_ADDRESS);
   
    baro.initialize();

    while (true) {
        baro.refreshPressure();
        usleep(10000); // Waiting for pressure data ready
        baro.readPressure();

        baro.refreshTemperature();		
        usleep(10000); // Waiting for temperature data ready
        baro.readTemperature();

        baro.calculatePressureAndTemperature();  

        printf("Temperature(C): %f Pressure(millibar): %fn", 
                baro.getTemperature(), baro.getPressure());
        sleep(1);
    }

    return 0;
}

More information about MS5611 is available in the datasheet

[Python]

Move to the folder with the code and run the example:

cd Navio/Python/Barometer
sudo python Barometer.py

You should see pressure and temperature values. Keep in mind that board tends to get hot from Raspberry and would show slightly higher temperature than it is in your room.

Temperature(C): 34.3509172821 Pressure(millibar): 1030.4646104
Temperature(C): 34.2971904755 Pressure(millibar): 1030.4639519
Temperature(C): 34.2795449066 Pressure(millibar): 1030.45554448
Temperature(C): 34.3018652344 Pressure(millibar): 1030.46921925