[CasperH2O]

We've been happily using this algorithm for motion sensor (IMU, gyroscope and accelerometer) filtering to game control input for some time in the open source application Handheld Companion [1].

There's also another nice page with explanation on how to tune the parameters [2] and there's a great visual with your mouse [3].

[1] https://github.com/Valkirie/HandheldCompanion

[2] https://gery.casiez.net/1euro/

[3] https://gery.casiez.net/1euro/InteractiveDemo/