Arduino Pro has still so little memory that I had to extrude and inline some code from libraries and stuff. The Kalman filtering code is from openxvario (check AsTra hw page for other inspirations). The code has also moving average filtering for debugging but (I think) only Kalman is used.AsTra is constrained by Arduino memory limits i.e. there is no room for all the functionality I would like it to have (e.g. Bluetooth data file transfer, local statistics etc).
Somewhat related projects: Climbing Sleeve, Ghost Climber, Augmented Climbing Wall
BMP820 has basic resolution of about 1 meter. For more accuracy (0.1 m) a sensor like MS5611 could be used. Check examples e.g. from my multiuser ascent tracker AsTra. As with any sensor, a longer integration time or filtering increases accuracy but hides quick changes.zymurgeneticist: what a great design! I would definitely use Trinket and other modern components for the next revision of AsTra. Only Arduino Pro was available when I started on late 2013. I have logged 4500 meters of ascents with AsTra since it was completeted about 18 months ago.There's a short demo video available it you are interested. I have added runtime statistics per climber to the code but I still have to document it before publishing it in GitHub.
Clearly convergent evolution. :-) Check my AsTra https://github.com/AscentTracker/AsTra for an alternative sensor and algorithms