This script is a technical analysis tool designed for the MetaTrader 4 platform. It utilizes Bollinger Bands—a common market indicator used to measure price volatility and identify potential trend directions—to automatically calculate dynamic "stop" levels and visual trend signals on a price chart.
Core Logic Overview
The primary goal of this script is to identify when a price is breaking out of its normal range and then track the "trailing" floor or ceiling of that movement. Instead of using static numbers, it calculates these points dynamically based on market momentum.
How it Works
1. Trend Identification The script constantly monitors the relationship between the current closing price and the Bollinger Bands.
- Bullish Momentum: If the price closes above the upper band, the tool identifies an upward trend.
- Bearish Momentum: If the price closes below the lower band, the tool identifies a downward trend.
2. Dynamic Stop Level Calculation Once a trend is established, the script calculates a "Stop" level (the protective boundary). It uses several layers of logic to ensure this level behaves intelligently:
- Expansion & Contraction: It looks at the distance between the upper and lower bands to determine the volatility of the current move.
- The Offset Factor: It incorporates a risk management factor (MoneyRisk) to adjust how much "breathing room" is given to the price, essentially widening or narrowing the stop distance based on user preference.
- Ratchet Mechanism (The "Non-Regression" Rule): This is a critical piece of logic. In an uptrend, the stop level is designed to only move upward; if the market dips but stays within the trend, the line remains at its highest previous point. Conversely, in a downtrend, the stop level only moves downward. This prevents the "stop" from moving backward into a zone of higher risk.
3. Visual Signaling and Display Options The script is highly customizable regarding what you see on your screen:
- Trend Lines: It can draw continuous lines representing the current active stop level.
- Signals: It can generate specific visual markers (arrows) to notify the user when a new trend has been confirmed or when a price has breached a significant boundary.
- Customization: Users can toggle between seeing just the signals, just the lines, or both, allowing for a clean chart layout depending on individual trading styles.
Summary for the Trader
Think of this tool as an automated "safety net" tracker. It watches for aggressive price breakouts and then draws a line that follows the price's progress. Because of its unique logic, that line will never move backward; it only moves in the direction of the trend (higher for buys, lower for sells), providing a clear visual of where a trend might be considered "broken" or invalidated.
//+------------------------------------------------------------------+
//| BBands_Stop_v1.mq4 |
//| Copyright © 2006, TrendLaboratory Ltd. |
//| http://finance.groups.yahoo.com/group/TrendLaboratory |
//| E-mail: igorad2004@list.ru |
//+------------------------------------------------------------------+
#property copyright "Copyright © 2006, TrendLaboratory Ltd."
#property link "http://finance.groups.yahoo.com/group/TrendLaboratory"
#property indicator_chart_window
#property indicator_buffers 6
#property indicator_color1 Chartreuse
#property indicator_color2 Orange
#property indicator_color3 Chartreuse
#property indicator_color4 Orange
#property indicator_color5 Chartreuse
#property indicator_color6 Orange
//---- input parameters
extern int Length=20; // Bollinger Bands Period
extern int Deviation=2; // Deviation
extern double x=0; // Tune
extern double MoneyRisk=1.00; // Offset Factor
extern int Signal=1; // Display signals mode: 1-Signals & Stops; 0-only Stops; 2-only Signals;
extern int Line=1; // Display line mode: 0-no,1-yes
extern int Nbars=1000;
//---- indicator buffers
double UpTrendBuffer[];
double DownTrendBuffer[];
double UpTrendSignal[];
double DownTrendSignal[];
double UpTrendLine[];
double DownTrendLine[];
//+------------------------------------------------------------------+
//| Custom indicator initialization function |
//+------------------------------------------------------------------+
int init()
{
string short_name;
//---- indicator line
SetIndexBuffer(0,UpTrendBuffer);
SetIndexBuffer(1,DownTrendBuffer);
SetIndexBuffer(2,UpTrendSignal);
SetIndexBuffer(3,DownTrendSignal);
SetIndexBuffer(4,UpTrendLine);
SetIndexBuffer(5,DownTrendLine);
SetIndexStyle(0,DRAW_ARROW);
SetIndexStyle(1,DRAW_ARROW);
SetIndexStyle(2,DRAW_ARROW);
SetIndexStyle(3,DRAW_ARROW);
SetIndexStyle(4,DRAW_LINE);
SetIndexStyle(5,DRAW_LINE);
SetIndexArrow(0,159);
SetIndexArrow(1,159);
SetIndexArrow(2,108);
SetIndexArrow(3,108);
IndicatorDigits(MarketInfo(Symbol(),MODE_DIGITS));
//---- name for DataWindow and indicator subwindow label
short_name="BBands Stop("+Length+","+Deviation+")";
IndicatorShortName(short_name);
SetIndexLabel(0,"UpTrend Stop");
SetIndexLabel(1,"DownTrend Stop");
SetIndexLabel(2,"UpTrend Signal");
SetIndexLabel(3,"DownTrend Signal");
SetIndexLabel(4,"UpTrend Line");
SetIndexLabel(5,"DownTrend Line");
//----
SetIndexDrawBegin(0,Length);
SetIndexDrawBegin(1,Length);
SetIndexDrawBegin(2,Length);
SetIndexDrawBegin(3,Length);
SetIndexDrawBegin(4,Length);
SetIndexDrawBegin(5,Length);
//----
return(0);
}
//+------------------------------------------------------------------+
//| Bollinger Bands_Stop_v1 |
//+------------------------------------------------------------------+
int start()
{
int i,shift,trend;
double smax[25000],smin[25000],bsmax[25000],bsmin[25000];
for (shift=Nbars;shift>=0;shift--)
{
UpTrendBuffer[shift]=0;
DownTrendBuffer[shift]=0;
UpTrendSignal[shift]=0;
DownTrendSignal[shift]=0;
UpTrendLine[shift]=EMPTY_VALUE;
DownTrendLine[shift]=EMPTY_VALUE;
}
for (shift=Nbars-Length-1;shift>=0;shift--)
{
smax[shift]=iBands(NULL,0,Length,Deviation,0,PRICE_CLOSE,MODE_UPPER,shift);
smin[shift]=iBands(NULL,0,Length,Deviation,0,PRICE_CLOSE,MODE_LOWER,shift);
if (Close[shift]>smax[shift+1]) trend=1;
if (Close[shift]<smin[shift+1]) trend=-1;
if(trend>0 && smin[shift]<smin[shift+1]) smin[shift]=smin[shift+1];
if(trend<0 && smax[shift]>smax[shift+1]) smax[shift]=smax[shift+1];
bsmax[shift]=smax[shift]+0.5*(MoneyRisk-1)*(smax[shift]-smin[shift]);
bsmin[shift]=smin[shift]-0.5*(MoneyRisk-1)*(smax[shift]-smin[shift]);
if(trend>0 && bsmin[shift]<bsmin[shift+1]) bsmin[shift]=bsmin[shift+1];
if(trend<0 && bsmax[shift]>bsmax[shift+1]) bsmax[shift]=bsmax[shift+1];
if (trend>0)
{
if (Signal>0 && UpTrendBuffer[shift+1]==-1.0)
{
UpTrendSignal[shift]=bsmin[shift];
UpTrendBuffer[shift]=bsmin[shift];
if(Line>0) UpTrendLine[shift]=bsmin[shift];
}
else
{
UpTrendBuffer[shift]=bsmin[shift];
if(Line>0) UpTrendLine[shift]=bsmin[shift];
UpTrendSignal[shift]=-1;
}
if (Signal==2) UpTrendBuffer[shift]=0;
DownTrendSignal[shift]=-1;
DownTrendBuffer[shift]=-1.0;
DownTrendLine[shift]=EMPTY_VALUE;
}
if (trend<0)
{
if (Signal>0 && DownTrendBuffer[shift+1]==-1.0)
{
DownTrendSignal[shift]=bsmax[shift];
DownTrendBuffer[shift]=bsmax[shift];
if(Line>0) DownTrendLine[shift]=bsmax[shift];
}
else
{
DownTrendBuffer[shift]=bsmax[shift];
if(Line>0)DownTrendLine[shift]=bsmax[shift];
DownTrendSignal[shift]=-1;
}
if (Signal==2) DownTrendBuffer[shift]=0;
UpTrendSignal[shift]=-1;
UpTrendBuffer[shift]=-1.0;
UpTrendLine[shift]=EMPTY_VALUE;
}
}
return(0);
}
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