From the forums: Rate of Climb Indicator for Gliders « Adafruit Industries – Makers, hackers, artists, designers and engineers!
DIY Arduino Variometer for Paragliding / Делаем Вариометр На Ардуино | Arduino, Diy, Gaming products
A Homebrew 11.7 uHy Variometer
variometer" 3D Models to Print - yeggi
The Variometer – How To Make | WG2XKA
How to make a Arduino variometer for paragliding | Hackaday.io
Arduino Variometer In A Mint Tin | Hackaday
E-paper gps variometer tracker (arduino compatible) for paragliding and gliding – E-paper instruments for paragliding and free flying that you can code yourself