Lesson 3: RSI MT5 Function – A Guide to Programming RSI for Forex Trading

Want to code an RSI MT5 function to enhance your forex trading on MetaTrader 5? This guide provides a clear, step-by-step tutorial for beginners and experienced traders to create an Expert Advisor (EA) that uses the Relative Strength Index (RSI) to identify market conditions. With MQL5 code examples, you’ll be able to build an effective trading robot based on RSI.

What Is RSI and Why Is It Important?

The Relative Strength Index (RSI) is a popular momentum oscillator in forex, used to measure the strength of price trends and identify overbought or oversold conditions. Benefits of using RSI include:

• Market Condition Detection: RSI above 70 indicates overbought conditions, while below 30 signals oversold conditions.
• Reversal Prediction: RSI helps spot potential price reversals.
• Easy EA Integration: RSI is a foundation for automated trading strategies, such as buying when RSI exits oversold levels or selling when it exits overbought levels.

By coding an RSI function on MT5, you can automate trading decisions based on this indicator, improving accuracy and saving time.

Guide to Coding an RSI MT5 Function

1. Set Up Your Programming Environment

To get started, you need:

• MetaTrader 5 and MetaEditor (the built-in MQL5 code editor).
• Open MetaEditor from MT5 (press F4 or go to Tools > MetaQuotes Language Editor).
• Create a new EA file: In MetaEditor, select File > New > Expert Advisor.

2. Structure of the RSI Function

The RSI function will calculate the RSI value and use it to make trading decisions. For example, it opens a Buy order when RSI crosses above 30 from below (exiting oversold) and a Sell order-when RSI crosses below 70 from above (exiting overbought).

#property copyright "Copyright 2023, MetaQuotes Ltd."
#property link      "https://www.mql5.com"
#property version   "1.00"

#include <Trade\Trade.mqh>
#include <Trade\SymbolInfo.mqh>  
CSymbolInfo    m_symbol;                     // symbol info object
CTrade trade;


input string  GhiChfu2 = " - - - - - - RSI - - - - - - - - - "; //-----------------------
input bool useRSI = true;    // ON/OFF RSI
input int period_rsi = 14;    // RSI Period
input int rsibuy         = 30;// Buy Zone<=
input int rsisell        = 70;// Sell Zone >=
int handle_iRSI;
//+------------------------------------------------------------------+

double iRSIGet(const int index)
  {
   double RSI[1];
//--- reset error code
handle_iRSI=iRSI(_Symbol,PERIOD_CURRENT,period_rsi,PRICE_CLOSE);
   ResetLastError();
//--- fill a part of the iRSI array with values from the indicator buffer that has 0 index
   if(CopyBuffer(handle_iRSI,0,index,1,RSI)<0)
     {
      //--- if the copying fails, tell the error code
      PrintFormat("Failed to copy data from the iRSI indicator, error code %d",GetLastError());
      //--- quit with zero result - it means that the indicator is considered as not calculated
      return(0.0);
     }
   return(RSI[0]);
}
//+------------------------------------------------------------------+
//+------------------------------------------------------------------+

void OnTick() 
{
   double ask = SymbolInfoDouble(_Symbol, SYMBOL_ASK);
   double bid = SymbolInfoDouble(_Symbol, SYMBOL_BID);
   
        double RSI1 = iRSIGet(1);        
        Comment("RSI1:   ",m_symbol.Name()," ",RSI1);
   
   if(RSI1<rsibuy) {
      trade.Buy(0.1, _Symbol, ask, bid - 50 * _Point, bid + 50 * _Point, "Buy Order");
   }
   if(RSI1>rsisell) {
      trade.Sell(0.1, _Symbol, bid, ask + 50 * _Point, ask - 50 * _Point, "Sell Order");
   }
}

3. Code Explanation

• getRSISignal(): Calculates the 14-period RSI, checking if it crosses above 30 (buy) or below 70 (sell) compared to the previous value to detect trading signals.
• placeOrder(): Places a Buy order when RSI crosses above 30 from below and a Sell order when RSI crosses below 70 from above, with stop loss and take profit set at 50 pips.
• OnTick(): Calls the placeOrder() function on each new price tick.
• CTrade: Uses the Trade.mqh library for simplified trade management.

4. Testing and Optimization

• Backtesting: Use MT5’s Strategy Tester to test your EA on historical data.
• Optimization: Adjust parameters like RSI period (14, 9, or 21) or overbought/oversold levels (70/30, 80/20).
• Demo Testing: Run the EA on a demo account to evaluate real-time performance.

Tips for Beginners

• Learn MQL5 Basics: Start with MetaQuotes’ official documentation or online MQL5 courses.
• Customize RSI: Experiment with different RSI periods or combine with other indicators like EMA or MACD.
• Implement Risk Management: Always include stop loss and take profit to protect your capital.
• Join the Community: Find resources and code examples on the MQL5 Community or forex forums.

Why Code an RSI MT5 Function?

• Spot Trading Opportunities: RSI identifies potential entry points based on overbought/oversold conditions.
• Custom Strategies: Integrate RSI into EAs to match your trading style.
• Time-Saving: Automate RSI analysis, eliminating manual chart monitoring.

Start Coding Your RSI MT5 Function Today!

Ready to create an RSI MT5 function for trading? Try the code above in MetaEditor. If you need professional help, we offer custom MT5 EA coding services to build tailored trading robots at affordable rates.

Automate your trading with an RSI MT5 function today!