Request: Integrate MPU9250 and BMP280 into VFRnav

VFRnav Support
1

@Hermann,

it would be awesome if the above chipsets, i.e. the 3-axis gyro + the tri-axis accelerometer and the BMP280, which for example are on the GY91 board, could be read/integrated into VFRnav.

Why, and for what?:

  • MPU9250 – not all aircraft have an artificial horizon built in. This would provide an inexpensive solution. Many Stratux units have this chipset installed, at least all those that have passed through my hands. The Stratux itself has long been interpreting the aforementioned MPU9250 and displays it as a horizon in the WebGUI. …an applet in VFRnav, e.g. a small icon in a corner, would be superb :folded_hands:

  • BMP280 – the sensor measures air pressure barometrically and provides the data. Also a classic, which is fitted in Stratux units or, in my case, additionally in the TTGo T-Beam. VFRnav can already read baro data from the phone (since it has such a sensor). So why not read the sensor from the Stratux? …the Bosch sensor should also have higher measurement accuracy than a phone.

→ …as always: I’m ready for pre-development and trialling. :star_struck::+1:

Yes, I know…for the phone pilots the display will become smaller with the integration of such features. Therefore, as always in VFRnav: optionally switchable via a control.

Pilot greetings, simply fly

Karsten

2

Hi Karsten,

after support for AHRS data – i.e. the attitude information for the artificial horizon – made its way into VFRnav 4.15, I was then able to look at your second suggestion as well.

My latest finding: with the NMEA sentence $PGRMZ, Stratux already provides additional altitude information. If a baro sensor is installed, this value corresponds to the barometric altitude based on standard atmosphere. That would be exactly the right basis for external pressure measurement for VFRnav’s altitude display.

The problem is this: if the Stratux has no baro installed, Stratux sends GPS altitude in the same sentence.

I therefore still need to examine more closely how to reliably distinguish the source of the PGRMZ altitude. Perhaps someone has an idea?

Why all this?
With the current pressure, which could be derived from the PGRMZ sentence, VFRnav could display barometric altitude according to the entered QNH – which, as is well known, is much more accurate than GPS altitude. It would also make it possible to implement a variometer.

That’s it for now on this topic.

Enjoy your holiday, @KBfly :slight_smile:

Hermann