Barometer (external)

Warning

Support for external barometers was released with Copter-3.6. The instructions below have been verified for the Drotek MS5611 and BMP280 types.

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Most flight controllers include a barometer directly on the flight controller but attaching an external barometer can be useful in order to place the barometer away from air pressure disturbances.

Note

Copter users can partially reduce the effect of air pressure disurbances by enabling Ground Effect Compensation

Tip

Besides providing pressure readings for altitude estimation, an additional barometer can be used for monitoring the environmental or an internal component’s temperature within a typical range of -40 - +85°C.

Where to Buy

Connecting and Configuring

Connect the barometer to the flight controller’s I2C port as shown below

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On the top of the Drotek MS5611 board, the “I2C” jumper should be soldered. Look for “I2C/SPI” written on the board.

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  • GND_PROBE_EXT to 4 for the Drotek MS5611 or 2 for the Adafruit BMP280. Reboot the flight controller after changing this parameter.
  • GND_PRIMARY to 1 to use the external barometer as the primary

Testing

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Real-time pressure and temperature from the barometer are sent to the ground station. If using Mission Planner they are visible on the Flight Data >> Status tab, look for “press_abs2” and “press_temp2”.

Mission Planner’s MAVLink Inspector can also be used to view the data. From the Flight Data screen press Ctrl-F, then push the “MAVLink In” button and then expand the view and look for SCALED_PRESSURE2.

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Tip

If using ArduPilot onboard OSD, the secondary barometer’s temperature reading can be displayed using the OSDn_BTEMP panel.