MQL4 Indicator passing signal to EA - indicator

Question

the problem is, I want to open order when my indicator gives signal. How can I do that?
I have been trying to do with iCustom() but it is not satisfying.
I tried to use GlobalVariableSet() in indicator and GlobalVariableGet() method in EA but it is not properly worked.
Please help.

Answer 1

The syntax is:
double iCustom(
string symbol, // symbol
int timeframe, // timeframe
string name, // path/name of the custom indicator compiled program
... // custom indicator input parameters (if necessary)
int mode, // line index
int shift // shift
);
Here is the example using custom Alligator indicator (which should be available by default as Alligator.mq4 in MT platform).
double Alligator[3];
Alligator[0] = iCustom(NULL, 0, "Alligator", 13, 8, 8, 5, 5, 3, 0, 0);
Alligator[1] = iCustom(NULL, 0, "Alligator", 13, 8, 8, 5, 5, 3, 1, 0);
Alligator[2] = iCustom(NULL, 0, "Alligator", 13, 8, 8, 5, 5, 3, 2, 0);
where 13, 8, 8, 5, 5, 3 are corresponding input parameters of custom Alligator as defined in indicator it-self:
//---- input parameters
input int InpJawsPeriod=13; // Jaws Period
input int InpJawsShift=8; // Jaws Shift
input int InpTeethPeriod=8; // Teeth Period
input int InpTeethShift=5; // Teeth Shift
input int InpLipsPeriod=5; // Lips Period
input int InpLipsShift=3; // Lips Shift
and mode is the corresponding line index as defined in the indicator by:
SetIndexBuffer(0, ExtBlueBuffer);
SetIndexBuffer(1, ExtRedBuffer);
SetIndexBuffer(2, ExtLimeBuffer);

Answer 2

The syntax is:
int signal = iCustom(NULL, 0, "MyCustomIndicatorName",
...parameters it takes in...,
...the buffer index you want from the custom indicator...,
...shift in bars);
Let's say you wrote a custom moving average indicator called "myMA" and it takes in a period only as one of its extern variables. This indicator calculates a simple moving average based on the period that the user supplies and on the close of each bar. This indicator stores its calculated values in an array MAValues[] that gets assigned to an index like this: SetIndexBuffer(0, MAValues);
To get the moving average of the current bar with period 200 then, you would write:
double ma_current_bar = iCustom(NULL, 0, "myMA", 200, 0, 0);
Then once you have this value you can check it against some trading criteria you determine, and open an order when it is met. For example if you wanted to open a long position if the moving average of the current bar equals the current Ask price, you would write:
if (ma_current_bar == Ask){
OrderSend(Symbol(), OP_BUY, 1, Ask, *max slippage*, *sl*, *tp*, NULL, 0, 0, GREEN);
}
This is just example code, do NOT use this in a live EA.