Change alpha coefficient to increase/decrease lag and smoothness.
Buy when crosses upwards above 20.
Sell when crosses down below 80.
While indicator runs flat above 80 level, it means that an uptrend is strong.
While indicator runs flat below 20 level, it means that a downtrend is strong.
In true TradingView spirit, the author of this script has published it open-source, so traders can understand and verify it. Cheers to the author! You may use it for free, but reuse of this code in a publication is governed by House Rules. You can favorite it to use it on a chart.