Quadsonde: low level atmospheric soundings using a small quadcopter

Hi there!

I’m jumping back into the autonomous vehicle hobby in an attempt to tackle a project that will be a huge help in my main hobby (paragliding)

When soaring in thermals in a paraglider, the “lapse rate” (temperature as you increase in altitude) controls how high you can get in a thermal. We look at the morning weather balloon soundings and the predictive weather models to get a decent look at how the day will develop, but having a real-time low-altitude soundings with a small quadcopter could be game-changing.

My current build plan is based off of this video:


Components (as outlined in video):

  • EMAX RS-II 1106 4500 Kv motors
  • Kakute F7 mini
  • FrSky R-XSR receiver with telemetry
  • Mateksys M8Q-5883 GPS/magnetometer
  • Mamba 306 ESC

The main addition to turn this into a sounding drone is planned to be BME 280 temp/humidity/pressure breakout board. I was planning on wiring this to the SDA and SCL pads on the flight controller. I believe this should work, even though the GPS/magnetometer will be on the same bus. (not 100% sure, but will research more)

The plan is to then run a two waypoint mission directly up (following local and federal laws of course), logging altitude, temperature, and tilt (for wind speed) to the internal memory of the flight controller. upon landing, the logged data could be downloaded to a PC, interpreted, and plotted to create a skew-T.

My questions are as follows:

  • Am I missing something? is there a better way to do this?

  • According to the firmware limitations page, it looks like external I2C barometers are disabled on the Kakute F7 mini. I think I’ll need this if I want to connect a BME280 and log the temperature throughout the flight…Is there a way to turn this back on (and maybe disable other features to save memory?)