<code>//+------------------------------------------------------------------+
//|                                                  PriceBorder.mq4 |
//|                                                 Copyright 2020,  |
//|                                      http://www.forexsystems.biz |
//+------------------------------------------------------------------+
#property copyright "Copyright 2020, "
#property link      "http://www.forexsystems.biz"
#property version   "1.00"
#property strict
#property indicator_chart_window

extern int MA=5;

extern string IndName    = "©Price Border (1)";
extern string TimeFrame = "All tf";
extern int HalfLength = 61;
extern int Price = 0;
extern double ATRMultiplier = 2.6;
extern int ATRPeriod = 110;
extern bool Interpolate = TRUE;

bool b=1,s=1;
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit()
  {
//--- indicator buffers mapping

//---
   return(INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int OnCalculate(const int rates_total,
                const int prev_calculated,
                const datetime &time[],
                const double &open[],
                const double &high[],
                const double &low[],
                const double &close[],
                const long &tick_volume[],
                const long &volume[],
                const int &spread[])
  {
//---
   double ma = NormalizeDouble(iMA(NULL,0,MA,0,0,0,0),_Digits);
   double up=iCustom(NULL,0,IndName,TimeFrame,HalfLength,Price,ATRMultiplier,ATRPeriod,Interpolate,1,0);
   double dn=iCustom(NULL,0,IndName,TimeFrame,HalfLength,Price,ATRMultiplier,ATRPeriod,Interpolate,2,0);
   
   if(Ask<ma && up<ma && Ask<dn && b)
     {
      Alert(_Symbol+" BUY!");
      b=0;
      s=1;
     }

   if(Bid>ma && dn>ma && Bid>up && s)
     {
      Alert(_Symbol+" SELL!");
      s=0;
      b=1;
     }

   Comment("\n UP: ",up,
           "\n DN: ",dn,
           "\n MA: ",ma,
           "\n BID: ",Bid);

//--- return value of prev_calculated for next call
   return(rates_total);
  }
//+------------------------------------------------------------------+
</code>