SMI

// Coded by FW
study("Stochastic Momentum Index", shorttitle = "SMI", overlay = false)
nn = input(5, "Period", minval = 1)
ns = input(3, "Smoothing", minval = 1)
nd = input(3, "Double Smoothing", minval = 1)
s = input(3, "Signal Period", minval = 1)

hh = highest(high, nn)
ll = lowest(low, nn)

ap = (hh + ll) / 2
range = (hh - ll)

k = 100 * (ema(ema(close - ap, ns), nd) / (ema(ema(range, ns), nd) / 2))
d = ema(k, s)
plot(k, color = blue, title = "Stochastic Momentum Index")
plot(d, color = red, title = "SMI Signal Line")
hline(40, color = red, title = "Overbought")
hline(-40, color = green, title = "Oversold")
hline(0, color = black, title = "Zero Line")