Bollinger Bands Buy Sell Signals — TradingView Guide

//@version=5
indicator("Bollinger Bands Buy Sell Signals", overlay=true)

bbLength = input.int(20, "BB Length")
bbMult = input.float(2.0, "BB Std Dev")
src = input.source(close, "Source")
squeezeLookback = input.int(20, "Squeeze Lookback", tooltip="Number of bars for squeeze comparison baseline")

// Bollinger Bands calculation
basis = ta.sma(src, bbLength)
dev = bbMult * ta.stdev(src, bbLength)
upper = basis + dev
lower = basis - dev

// Band width
bandWidth = upper - lower
avgBandWidth = ta.sma(bandWidth, squeezeLookback)

// %B indicator
pctB = (src - lower) / (upper - lower)

// Buy signal: price touches lower band, closes back inside
lowerTouch = low <= lower
lowerBounce = close > lower
buySignal = lowerTouch and lowerBounce and close > open

// Sell signal: price touches upper band, closes back inside
upperTouch = high >= upper
upperReject = close < upper
sellSignal = upperTouch and upperReject and close < open

// Squeeze detection
isSqueeze = bandWidth < avgBandWidth and bandWidth < bandWidth[squeezeLookback]
squeezeBreakoutUp = isSqueeze[1] and close > upper
squeezeBreakoutDown = isSqueeze[1] and close < lower

// Band walk detection: 3+ consecutive closes outside a band
walkUp = close > upper and close[1] > upper[1] and close[2] > upper[2]
walkDown = close < lower and close[1] < lower[1] and close[2] < lower[2]

// Plot Bollinger Bands
plot(basis, "Basis", color=#2962FF, linewidth=2)
p1 = plot(upper, "Upper", color=#FF5252, linewidth=1)
p2 = plot(lower, "Lower", color=#4CAF50, linewidth=1)
fill(p1, p2, color=color.new(color.gray, 92), title="Band Fill")

// Plot buy and sell signals on the price chart
plotshape(buySignal, "Buy Signal", shape.triangleup, location.belowbar, color=#4CAF50, size=size.small)
plotshape(sellSignal, "Sell Signal", shape.triangledown, location.abovebar, color=#FF5252, size=size.small)

// Squeeze markers
plotshape(squeezeBreakoutUp, "Squeeze Buy", shape.labelup, location.belowbar, color=#00BCD4, size=size.small)
plotshape(squeezeBreakoutDown, "Squeeze Sell", shape.labeldown, location.abovebar, color=#FF9800, size=size.small)

// Band walk labels
plotshape(walkUp, "Band Walk Up", shape.circle, location.abovebar, color=#E040FB, size=size.tiny)
plotshape(walkDown, "Band Walk Down", shape.circle, location.belowbar, color=#E040FB, size=size.tiny)

// Band width subplot
hline(0, "Zero Line", color=#757575, linestyle=hline.style_dotted)
plot(bandWidth, "Band Width", color=#757575, display=display.none)

alertcondition(buySignal, "BB Lower Band Bounce Buy", "Price closed above the lower Bollinger Band after touching it")
alertcondition(sellSignal, "BB Upper Band Rejection Sell", "Price closed below the upper Bollinger Band after touching it")
alertcondition(isSqueeze, "BB Squeeze", "Bollinger Band width is at a multi-period low")
alertcondition(squeezeBreakoutUp, "BB Squeeze Breakout Up", "Price broke above upper band after a squeeze")
alertcondition(squeezeBreakoutDown, "BB Squeeze Breakout Down", "Price broke below lower band after a squeeze")