study(title="ALERTS FOR BINARY OPTIONS")

//inputs
E = input(1, minval=1, title="No. of candles to Expiry")
length = input(20, minval=1)
src = input(close, title="Source")
mult = input(2.15, minval=0.001, maxval=50, title="StdDev")


//Bollinger bands
f_bb(src, length, mult) =>
    basis = sma(src, length)
    dev = mult * stdev(src, length)
    [basis, basis + dev, basis - dev]

[middle, upper, lower] = f_bb(close, 20, 2.15)

//bollinger bands %age deviation
basis = sma(src, length)
dev = mult * stdev(src, length)
upperr = basis + dev
lowerr = basis - dev
bbr = (src - lowerr)/(upperr - lower)

//BB close filter
bbup_filter = close[3]<upper[3]  and close[2]<upper[2] and  close[1]<upper[1]
bblow_filter = close[3]>lower[3]  and close[2]>lower[2] and  close[1]>lower[1]

//Call or put
PUT = (close>upper and close[1]<upper[1] and bbr>1.0 and bbup_filter)
CALL = (close<lower and close[1]>lower[1] and bbr<0.0 and bblow_filter) 


alertcondition(PUT,  "TAKE PUT",  "EXPIRY 1 MIN")
alertcondition(CALL, "TAKE CALL", "EXPIRY 1 MIN")