Theory :

EMA (Exponential Moving Average) is very well known and widely used indicator. More information on it can be found here : https://en.wikipedia.org/wiki/Moving_average. It is used as a building brick for TRIX (triple exponential average (TRIX) indicator is an oscillator used to identify oversold and overbought markets, and it can also be used as a momentum indicator.

This version :

Is using the "Fast EMA" variation (originally published here : Fast EMA) instead of using "regular" EMA for TRIX calculation. That makes it faster in response to market changes than the original TRIX indicator

Usage :

You can use this version the usual way - change of color can be used as a signal