https://github.com/CodinalSystems/BarChangeTimer/blob/master/BarChangeTimer.mq4

//+------------------------------------------------------------------+
//|                                               BarChangeTimer.mq4 |
//|                                                  Codinal Systems |
//|                                             https://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Codinal Systems"
#property link      "https://codinal-systems.com/"
#property version   "1.00"
#property strict

enum TimerPos {
    LEFT_UPPER, //左上
    RIGHT_UPPER, //右上
    LEFT_LOWER,//左下
    RIGHT_LOWER //右下
};

int input timerSize = 24; //文字大小
color input timerColor = clrWhite; //文字颜色
input TimerPos timerPos = RIGHT_LOWER; // corner
input int PosX = 0; //X 坐标
input int PosY = 0; //Y 坐标
input int colorChangeTime = 10; // 倒计时变更颜色秒数
input color colorChange = clrRed; //倒计时变更颜色

void OnInit() {

    ObjectCreate("TimerObj", OBJ_LABEL, 0, 0, 0);

    switch(timerPos) {

    case LEFT_UPPER:
        ObjectSetInteger(0, "TimerObj", OBJPROP_CORNER, CORNER_LEFT_UPPER);
        ObjectSetInteger(0, "TimerObj", OBJPROP_ANCHOR, ANCHOR_LEFT_UPPER);
        break;

    case RIGHT_UPPER:
        ObjectSetInteger(0, "TimerObj", OBJPROP_CORNER, CORNER_RIGHT_UPPER);
        ObjectSetInteger(0, "TimerObj", OBJPROP_ANCHOR, ANCHOR_RIGHT_UPPER);
        break;

    case LEFT_LOWER:
        ObjectSetInteger(0, "TimerObj", OBJPROP_CORNER, CORNER_LEFT_LOWER);
        ObjectSetInteger(0, "TimerObj", OBJPROP_ANCHOR, ANCHOR_LEFT_LOWER);
        break;

    case RIGHT_LOWER:
        ObjectSetInteger(0, "TimerObj", OBJPROP_CORNER, CORNER_RIGHT_LOWER);
        ObjectSetInteger(0, "TimerObj", OBJPROP_ANCHOR, ANCHOR_RIGHT_LOWER);
        break;
    }

    ObjectSetInteger(0, "TimerObj", OBJPROP_XDISTANCE, PosX);
    ObjectSetInteger(0, "TimerObj", OBJPROP_YDISTANCE, PosY);
    ObjectSetText("TimerObj", "", timerSize, "Meiryo UI", timerColor);
    EventSetTimer(1);
}

void deinit() {

    ObjectDelete("TimerObj");
}

//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+
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[]) {
    return(rates_total);
}

void OnTimer() {

    int secRemaining = Time[0] + PeriodSeconds() - TimeCurrent();
    int hour = secRemaining / 3600;
    int min = (secRemaining / 60) % 60;
    int sec = secRemaining - min * 60 - hour * 3600;

    string minStr = AddZero(min);
    string secStr = AddZero(sec);
    string TimeText;

    if(Period() <= 60) {
        TimeText = minStr + ":" + secStr;
    } else {
        TimeText = hour + ":" + minStr + ":" + secStr;
    }

    ObjectSetText("TimerObj", TimeText);

    if (hour == 0 && min == 0 && sec < colorChangeTime) {
        ObjectSet("TimerObj", OBJPROP_COLOR, colorChange);
    }

}

string AddZero(int time) {

    if (time > 0 && time < 10) {
        return "0" + (string)time;
    } else if (time <= 0) {
        return "00"; 
    } else {
        return (string)time;
    }
}
//+------------------------------------------------------------------+