Słomkowski's technical musings

Playing with software, hardware and touching the sky with paraglider.

Cheap flight computer combining Kobo Mini and BlueFly Vario module


Using ebook reader Kobo Mini with BlueFly Vario is a really cheap alternative for of-the-shelf paraglider variometers. I built one with custom 3D-printed case.

Vario- and altimeter is a must if you do free-flying, but even with paramotor it’s nice to have one. These devices are not cheap so I decided to build one following this tutorial. I’ve seen people doing contraptions like this, for my device I have following requirements:

Apart from combining XCSoar, Kobo Mini and Blue Fly Vario, I designed in FreeCad custom 3D-printed case for the module so everything sits together nice and tight. The project repository is on GitHub. The case has holes, so Blue Fly’s speaker is clearly audible even with noise-muffling headset. Despite this, I added mini jack socket for connecting vario speaker to the headset. Speaker’s volume is adjustable using Blue Fly’s commands. To the back of the Kobo I glued stripes of velcro tape, so I can easily attach the reserve compartment as shown on the photo.

The module’s pressure sensor is secured with piece of foam as described in the manual. The case has holes for the speaker, they are covered with a piece of dark cloth. There is also a piece of rope attached to the case which prevents the device from flying away in unlikely case of velcro failure.

The case is attached to Kobo by two M3 screws with nuts. First you have to put the case on the Kobo and mark the holes positions. The holes are positioned in such way that they don’t collide with electronics but be careful when drilling.