Pls help for alarm

[Forex Trader]

In the following indicator, there are 3 colors : green (up),red (down) and yellow(flat).

How can I add an alarm message when color changes ?

double ExtMapBuffer1[];
double ExtMapBuffer2[];
double ExtMapBuffer3[];
int width;

extern int Rperiod = 34;
extern int Draw4HowLongg = 300; // 500 // 1000
int Draw4HowLong;
int shift;
int i;
int loopbegin;
double sum[];
int length;
double lengthvar;
double tmp ;
double wt[];
int c;

//+------------------------------------------------------------------+
//| Custom indicator initialization function |
//+------------------------------------------------------------------+
int init()
{
//---- 2 additional buffers are used for counting.
IndicatorBuffers(5);

//---- drawing settings
SetIndexBuffer(2,ExtMapBuffer1);
SetIndexBuffer(1,ExtMapBuffer2);
SetIndexBuffer(0,ExtMapBuffer3);
SetIndexBuffer(3,sum);
SetIndexBuffer(4,wt);

SetIndexStyle(2,DRAW_LINE,STYLE_SOLID,3);
SetIndexStyle(1,DRAW_LINE,STYLE_SOLID,3);
SetIndexStyle(0,DRAW_LINE,STYLE_SOLID,3);

//---- initialization done
return(0);
}

int start()

{ Draw4HowLong = Bars-Rperiod - 5;
length = Rperiod;
loopbegin = Draw4HowLong - length - 1;

for(shift = loopbegin; shift >= 0; shift--)
{
sum[1] = 0;
for(i = length; i >= 1 ; i--)
{
lengthvar = length + 1;
lengthvar /= 3;
tmp = 0;
tmp = ( i - lengthvar)*Close[length-i+shift];
sum[1]+=tmp;
}
wt[shift] = sum[1]*6/(length*(length+1));

//========== COLOR CODING ===========================================

ExtMapBuffer3[shift] = wt[shift]; //red
ExtMapBuffer2[shift] = wt[shift]; //green
ExtMapBuffer1[shift] = wt[shift]; //yellow

// for(c=loopbegin;c==shift;c++)
// {
if (wt[shift+1] > wt[shift])
{
ExtMapBuffer2[shift+1] = EMPTY_VALUE;
// ObjectCreate("smiley_face", OBJ_ARROW, 0, Time[shift], Low[shift]-Point*20);
// Print("time= ",Time[shift]);
// ObjectSet("smiley_face", OBJPROP_ARROWCODE, 242);
// ObjectSet("smiley_face", OBJPROP_COLOR , Red);
// ObjectSet("smiley_face", OBJPROP_WIDTH , 1);
// ObjectsRedraw();

//ExtMapBuffer3[shift+1] = EMPTY_VALUE;
//ExtMapBuffer3[shift+1] = EMPTY_VALUE;

}
else if (wt[shift+1] < wt[shift])
{
ExtMapBuffer1[shift+1] = EMPTY_VALUE; //-1 red/greem tight
MessageBox("asda");

//ExtMapBuffer3[shift+1] = EMPTY_VALUE;

}
else
{

ExtMapBuffer1[shift+1]=CLR_NONE;//EMPTY_VALUE;
ExtMapBuffer2[shift+1]=CLR_NONE;//EMPTY_VALUE;
}

}

return(0);
}
//+------------------------------------------------------------------+