The High Low Activator Indicator was described by Robert Krausz in a 1998 issue of Stocks & Magazine. It is a of the previous n period's highs or lows.
The indicator tracks both curves (of the highs and the lows). The close of the bar defines which of the two gets plotted.
This version is showing the channel that needs to be broken if the trend is going to be changed, and it allows you to chose from the 4 basic averages type for calculation (by definition, High Low Activator uses only , but some other averages can give you results that are probably more acceptable for trading in some conditions).
Increasing HPeriod and decreasing LPeriod better for short trades, vice versa for long positions.
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.