Variometer with mechanical needle and LCD for use with Openvario. Can also be used for simulators. Work in progress.

This is a standard 60x60mm instrument (57mm diameter hole). Its designed around the x27.168 automotive gauge stepper motor, a rotary encoder (Keyes 040 for now) and one of these two displays:

• 1.3" SHARP Memory LCD.
• 1.54" Waveshare E-ink display

Both displays are are perfectly sunlight readable, but have no backlight. Cockpit sim builders may want to use an OLED instead, and will have to modify the design.

The eink displays looks a little better, is larger and has a higher resolution; but the update rate is slow, on the order of 2 frames per second.

This 5V stepper can be driven directly from an arduino, but for smoother movement, I recommend you use a microstepper controller like the AX1201728SG. More info here: https://guy.carpenter.id.au/gaugette/2017/04/29/switecx25-quad-driver-tests/

For use with Openvario, the code is still being worked on, you can follow this project here: https://forum.xcsoar.org/viewtopic.php?f=30&t=3062

I will modify the design to hold the electronics later once I settled on the components. For now, you'll have house them externally or make something yourself.

The 3 main bolts are M4 sized and friction fit for now. For the encoder, also use M4 bolt or a smooth shaft. 2 M3 bolts are used to hold modules together during assembly.