The Waddah Attar explosion indicator is a well known indi in the forex community all over the web. It measures the price "explosion" with the help of a difference between upper and lower (also known as "squeeze") and its direction and with a slow advance or decline weighted with a coefficient (sensitivity=150).
A "deadzone" of x pips/points is at 20 points by default, but should be adjusted to the traded instrument.
If green or red oscillator histogram breach the "Explosion Line" above the dead zone, it's a signal.
This indicator act pretty much as a scalper in lower timeframe, but I found it useful with different timeframe comparison in higher ones in the past (M30/H1/H4).
Credits to http://www.prorealcode.com/prorealtime-indicators/waddah-attar-explosion/