The Z-indicator is popular in the statistics. What if we use it to identify the tops and bottoms. Very simple indicator.
//@version=2
study("[蘆田资產]Z-score Indicator")
length=input(20,"Length")
smooth1=input(3,"Smooth")
smooth2=input(5,"Smooth")
upStd=input(2, "Up Standard Deviation")
downStd=input(-2, "Down Standard Deviation")
z = stdev(close, length) != 0 ? (close - sma(close, length))/stdev(close, length) : na
ind1 = sma(z, smooth1)
ind2 = sma(ind1, smooth2)
plot(ind1, "Ind Fast", color = purple, linewidth=3)
plot(ind2, "Ind Slow", color = blue, linewidth=3)
plot(upStd, "Up Std Dev", color = lime, linewidth=3)
plot(downStd, "Down Std Dev", color = red, linewidth=3)