BB + RSI Double Cross Strategy - Technical Guide

Computes Bollinger Bands and RSI, plots L/S signals when RSI crosses the trigger while price crosses a band edge, and draws trend markers.


Language	Indie Script v5
Platform	TakeProfit
Category	Oscillators
Type	Indicator
Author	@insurgent on TakeProfit
Original	Based on ChartArt’s strategy concept (v1.1)
License	MIT
Live script	Open on TakeProfit
Source file	BB + RSI Double Cross Strategy.indie5

Overview

An overlay indicator that draws Bollinger Bands with a filled zone and marks mean-reversion signals when RSI and price confirm each other. It is intended for setups where price reaches a band extreme and RSI starts to turn through its trigger level.

On every bar, the script computes RSI and Bollinger Bands and draws L labels at the lower band when RSI crosses above the trigger while price crosses above the lower band. It draws S labels at the upper band when RSI crosses below the trigger while price crosses below the upper band. Optional trend markers appear when price re-enters the bands and the basis line is moving in the same direction.

How it works

Computes Rsi.new(self.close, rsi_length) and Bb.new(self.close, bb_length, bb_mult); reading [0] gives the current bar value and [1] the previous bar.
Long signal: cross_over(vrsi, float(rsi_level)) and cross_over(self.close, bb_lower) are both true on the same bar.
Short signal: cross_under(vrsi, float(rsi_level)) and cross_under(self.close, bb_upper) are both true on the same bar.
Trend red: previous close was above the upper band and current close is below it while bb_basis[0] < bb_basis[1].
Trend green: previous close was at the lower band and current close is above it while bb_basis[0] > bb_basis[1].
If show_signals is on, draws L at bb_lower[0] or S at bb_upper[0] and increments long_count / short_count.
If show_trend_marks is on, draws Down at high[0] or Up at low[0] for the corresponding marker.
Returns the current lower, basis, and upper values plus plot.Fill() to complete the plotted band and fill.

Mathematical model

\[b_t = \frac{1}{n}\sum_{i=0}^{n-1} c_{t-i}\] \[u_t = b_t + m\,\sigma_t,\quad l_t = b_t - m\,\sigma_t,\quad \sigma_t = \sqrt{\frac{1}{n}\sum_{i=0}^{n-1}\left(c_{t-i} - b_t\right)^2}\] \[RSI_t = 100 - \frac{100}{1 + RS_t},\quad RS_t = \frac{SMA(\max(c_t - c_{t-1},0),n)}{SMA(\max(c_{t-1} - c_t,0),n)}\]

Logic flow

flowchart TD
A["Compute RSI and BB per bar"] --> B{"RSI crossed above trigger and price crossed above lower band"}
B -- yes --> C["Draw L label and increment long count"]
B -- no --> D{"RSI crossed below trigger and price crossed below upper band"}
D -- yes --> E["Draw S label and increment short count"]
D -- no --> F{"Price re-entered from above upper band"}
F -- yes --> G{"Basis is falling"}
G -- yes --> H["Draw red Down marker"]
G -- no --> I{"Price re-entered from below lower band"}
F -- no --> I
I -- yes --> J{"Basis is rising"}
J -- yes --> K["Draw green Up marker"]
J -- no --> L["Update info panel and plot bands"]
K --> L
H --> L
C --> L
E --> L

Parameters

Parameter	Type	Default	Range	Description
`rsi_length`	int	6	≥ 1	RSI Period
`bb_length`	int	200	≥ 1	BB Period
`bb_mult`	float	2.0	0.001 - 50.0	BB StdDev
`rsi_level`	int	50	0 - 100	RSI Trigger Level
`show_signals`	bool	true		Show Signal Labels
`show_trend_marks`	bool	true		Show Trend Markers

Code walkthrough

Indicator declaration and plot setup

Lines 30-40 of BB + RSI Double Cross Strategy.indie5:

@indicator('BB + RSI Double Strategy', overlay_main_pane=True)
@param.int('rsi_length', default=6, min=1, title='RSI Period')
@param.int('bb_length', default=200, min=1, title='BB Period')
@param.float('bb_mult', default=2.0, min=0.001, max=50.0, title='BB StdDev')
@param.int('rsi_level', default=50, min=0, max=100, title='RSI Trigger Level')
@param.bool('show_signals', default=True, title='Show Signal Labels')
@param.bool('show_trend_marks', default=True, title='Show Trend Markers')
@plot.line('lower', color=color.SILVER, title='BB Lower')
@plot.line('basis', color=color.AQUA, title='BB Basis')
@plot.line('upper', color=color.SILVER, title='BB Upper')
@plot.fill('lower', 'upper', color=color.SILVER(0.1), title='BB Zone')

The decorators define the indicator name, main-pane overlay, user-facing parameters, and the three plotted series. @plot.fill('lower', 'upper', ...) creates the translucent zone between the lower and upper bands.

State and info label

Lines 42-51 of BB + RSI Double Cross Strategy.indie5:

    def __init__(self):
        self.long_count = 0
        self.short_count = 0
        self.info_label = LabelRel(
            "",
            RelativePosition(va.TOP, ha.RIGHT, 0.02, 0.98),
            font_size=11,
            text_color=color.WHITE,
            bg_color=color.rgba(30, 30, 60, 0.9)
        )

long_count and short_count are instance fields, so they survive across bars. The info label is a LabelRel anchored to the top-right corner and redrawn every bar.

Signal computation

Lines 55-66 of BB + RSI Double Cross Strategy.indie5:

        vrsi = Rsi.new(self.close, rsi_length)
        bb_lower, bb_basis, bb_upper = Bb.new(self.close, bb_length, bb_mult)
        
        # LONG: RSI crosses above level AND price crosses above lower BB
        rsi_cross_up = cross_over(vrsi, float(rsi_level))
        price_cross_up_lower = cross_over(self.close, bb_lower)
        long_signal = rsi_cross_up and price_cross_up_lower
        
        # SHORT: RSI crosses below level AND price crosses below upper BB
        rsi_cross_down = cross_under(vrsi, float(rsi_level))
        price_cross_down_upper = cross_under(self.close, bb_upper)
        short_signal = rsi_cross_down and price_cross_down_upper

Rsi.new and Bb.new return series; [0] is the current bar and [1] is the previous bar. cross_over / cross_under compare the latest bar with the previous one. Both legs of the long and short conditions must be true on the same bar.

Trend marker conditions

Lines 68-70 of BB + RSI Double Cross Strategy.indie5:

        # Trend color conditions
        trend_red = (self.close[1] > bb_upper[1] and self.close[0] < bb_upper[0]) and (bb_basis[0] < bb_basis[1])
        trend_green = (self.close[1] < bb_lower[1] and self.close[0] > bb_lower[0]) and (bb_basis[0] > bb_basis[1])

A red marker needs the close to fall back inside the upper band while the basis is declining. A green marker needs the close to rise back inside the lower band while the basis is rising.

Drawing signal labels

Lines 72-94 of BB + RSI Double Cross Strategy.indie5:

        # Draw signal labels
        if show_signals:
            if long_signal:
                self.long_count += 1
                self.chart.draw(LabelAbs(
                    "L",
                    AbsolutePosition(self.time[0], bb_lower[0]),
                    font_size=12,
                    text_color=color.WHITE,
                    bg_color=color.GREEN,
                    callout_position=cp.TOP_RIGHT
                ))
            
            if short_signal:
                self.short_count += 1
                self.chart.draw(LabelAbs(
                    "S",
                    AbsolutePosition(self.time[0], bb_upper[0]),
                    font_size=12,
                    text_color=color.WHITE,
                    bg_color=color.RED,
                    callout_position=cp.BOTTOM_RIGHT
                ))

Labels are placed at the band price that triggered the signal. Long labels are green with white text and short labels are red, with callout positions pointing to the relevant band.

Info panel and return values

Lines 117-133 of BB + RSI Double Cross Strategy.indie5:

        # Update info panel
        info_text = "BB + RSI Strategy"
        info_text += "\n─────────────"
        info_text += "\nRSI(" + str(rsi_length) + "): " + str(round(vrsi[0], 1))
        info_text += "\nBB(" + str(bb_length) + "): " + str(round(bb_basis[0], 2))
        info_text += "\n─────────────"
        info_text += "\nLONG: " + str(self.long_count)
        info_text += "\nSHORT: " + str(self.short_count)
        
        self.info_label.text = info_text
        self.chart.draw(self.info_label)
        
        return (
            bb_lower[0],
            bb_basis[0],
            bb_upper[0],
            plot.Fill()

The info panel is a single LabelRel whose text is replaced every bar. The tuple returned from calc supplies the current values of the three bands plus an empty fill marker for the decorated plot.

Reading the chart

The silver lines are the lower and upper Bollinger Bands; the aqua line is the SMA basis. The translucent silver fill visually marks the band zone.
A white L on a green label at the lower band means the long signal fired on that bar. A white S on a red label at the upper band means the short signal fired.
A red Down label at the high appears when price closes back below the upper band while the basis is falling.
A green Up label at the low appears when price closes back above the lower band while the basis is rising.
The top-right panel shows the current RSI value, the current BB basis, and the cumulative number of L and S labels drawn.

Implementation notes

long_count and short_count are initialized once in __init__, so they count every signal drawn across the life of the indicator.
Signal and trend labels are only drawn when the corresponding boolean parameters are enabled; the calculations still run every bar.
The info panel uses one LabelRel object whose text is updated and redrawn on each bar, so only the latest values are visible.
Band plots return [0] values from calc, so the chart receives one scalar per series per bar.

FAQ

What do the L and S labels represent?

L means the long signal condition fired: RSI crossed above the trigger level and price crossed above the lower band. S means the short signal condition fired: RSI crossed below the trigger and price crossed below the upper band.

Does this code open or close trades?

No. It only computes signals and draws labels and an info panel. There is no order execution or position management in the source.

How can I make the signals react faster or slower?

Lowering rsi_length makes RSI more responsive; raising bb_length or bb_mult makes the bands wider so triggers happen less often. The exact effect depends on the chart timeframe and the market.

Full source code

Indie Script v5, as published on TakeProfit. Copy it into the platform’s script editor or open the live script.

# indie:lang_version = 5
#
# Bollinger Bands + RSI Double Cross Strategy Indicator
# Based on ChartArt's strategy concept (v1.1)
#
# This indicator combines RSI momentum with Bollinger Bands volatility to identify
# high-probability reversal points. Signals are generated only when BOTH conditions
# align simultaneously, filtering out false signals common in single-indicator systems.
#
# SIGNAL LOGIC:
# - LONG:  RSI crosses ABOVE 50 AND Price crosses ABOVE lower BB (bullish reversal)
# - SHORT: RSI crosses BELOW 50 AND Price crosses BELOW upper BB (bearish reversal)
#
# The strategy targets mean-reversion setups where price has reached BB extremes
# and RSI confirms momentum shift through the 50 centerline.
#
# TREND COLOR MARKERS:
# - Red (Down ▼):  Price re-enters from above upper BB while basis is declining
# - Green (Up ▲): Price re-enters from below lower BB while basis is rising
#
from indie import indicator, param, color, plot, MainContext
from indie.algorithms import Rsi, Bb
from indie.math import cross_over, cross_under
from indie.drawings import (
    LabelAbs, LabelRel, AbsolutePosition, RelativePosition,
    vertical_anchor as va, horizontal_anchor as ha, callout_position as cp
)


@indicator('BB + RSI Double Strategy', overlay_main_pane=True)
@param.int('rsi_length', default=6, min=1, title='RSI Period')
@param.int('bb_length', default=200, min=1, title='BB Period')
@param.float('bb_mult', default=2.0, min=0.001, max=50.0, title='BB StdDev')
@param.int('rsi_level', default=50, min=0, max=100, title='RSI Trigger Level')
@param.bool('show_signals', default=True, title='Show Signal Labels')
@param.bool('show_trend_marks', default=True, title='Show Trend Markers')
@plot.line('lower', color=color.SILVER, title='BB Lower')
@plot.line('basis', color=color.AQUA, title='BB Basis')
@plot.line('upper', color=color.SILVER, title='BB Upper')
@plot.fill('lower', 'upper', color=color.SILVER(0.1), title='BB Zone')
class Main(MainContext):
    def __init__(self):
        self.long_count = 0
        self.short_count = 0
        self.info_label = LabelRel(
            "",
            RelativePosition(va.TOP, ha.RIGHT, 0.02, 0.98),
            font_size=11,
            text_color=color.WHITE,
            bg_color=color.rgba(30, 30, 60, 0.9)
        )

    def calc(self, rsi_length, bb_length, bb_mult, rsi_level, show_signals, show_trend_marks):
        # Calculate indicators
        vrsi = Rsi.new(self.close, rsi_length)
        bb_lower, bb_basis, bb_upper = Bb.new(self.close, bb_length, bb_mult)
        
        # LONG: RSI crosses above level AND price crosses above lower BB
        rsi_cross_up = cross_over(vrsi, float(rsi_level))
        price_cross_up_lower = cross_over(self.close, bb_lower)
        long_signal = rsi_cross_up and price_cross_up_lower
        
        # SHORT: RSI crosses below level AND price crosses below upper BB
        rsi_cross_down = cross_under(vrsi, float(rsi_level))
        price_cross_down_upper = cross_under(self.close, bb_upper)
        short_signal = rsi_cross_down and price_cross_down_upper
        
        # Trend color conditions
        trend_red = (self.close[1] > bb_upper[1] and self.close[0] < bb_upper[0]) and (bb_basis[0] < bb_basis[1])
        trend_green = (self.close[1] < bb_lower[1] and self.close[0] > bb_lower[0]) and (bb_basis[0] > bb_basis[1])
        
        # Draw signal labels
        if show_signals:
            if long_signal:
                self.long_count += 1
                self.chart.draw(LabelAbs(
                    "L",
                    AbsolutePosition(self.time[0], bb_lower[0]),
                    font_size=12,
                    text_color=color.WHITE,
                    bg_color=color.GREEN,
                    callout_position=cp.TOP_RIGHT
                ))
            
            if short_signal:
                self.short_count += 1
                self.chart.draw(LabelAbs(
                    "S",
                    AbsolutePosition(self.time[0], bb_upper[0]),
                    font_size=12,
                    text_color=color.WHITE,
                    bg_color=color.RED,
                    callout_position=cp.BOTTOM_RIGHT
                ))
        
        # Draw trend markers
        if show_trend_marks:
            if trend_red:
                self.chart.draw(LabelAbs(
                    "Down",
                    AbsolutePosition(self.time[0], self.high[0]),
                    font_size=12,
                    text_color=color.RED,
                    bg_color=color.rgba(0, 0, 0, 0),
                    callout_position=cp.BOTTOM_RIGHT
                ))
            elif trend_green:
                self.chart.draw(LabelAbs(
                    "Up",
                    AbsolutePosition(self.time[0], self.low[0]),
                    font_size=12,
                    text_color=color.GREEN,
                    bg_color=color.rgba(0, 0, 0, 0),
                    callout_position=cp.TOP_RIGHT
                ))
        
        # Update info panel
        info_text = "BB + RSI Strategy"
        info_text += "\n─────────────"
        info_text += "\nRSI(" + str(rsi_length) + "): " + str(round(vrsi[0], 1))
        info_text += "\nBB(" + str(bb_length) + "): " + str(round(bb_basis[0], 2))
        info_text += "\n─────────────"
        info_text += "\nLONG: " + str(self.long_count)
        info_text += "\nSHORT: " + str(self.short_count)
        
        self.info_label.text = info_text
        self.chart.draw(self.info_label)
        
        return (
            bb_lower[0],
            bb_basis[0],
            bb_upper[0],
            plot.Fill()
        )