A rudimentary timer (low granularity), that doesn't lock IGOR up.

//a background task that you can use to wait for a given timeperiod.  This is probably called from
//another background task.  This is useful if you don't want to lock IGOR up. (original by andyfaff)
//Upgrades by Stefan Mangold, using multiple alarms, executing one task per timer


// startwaitAndExecuteTaskUnified, best option

Function startwaitAndExecuteTaskUnified(timeout,type,TaskName)
    variable timeout, type
    string TaskName
    if(exists("root:numberOfWaiter")==0)
        variable/g root:numberOfWaiter
        NVar numberOfWaiterG = root:numberOfWaiter
        numberOfWaiterG = 0
    else
        NVar numberOfWaiterG = root:numberOfWaiter
    endif  
   
   
    if(numberOfWaiterG == 0)
        make/D/O/N=(numberOfWaiterG+1) root:endtimeW
        make/D/O/N=(numberOfWaiterG+1) root:typeW
        make/T/O/N=(numberOfWaiterG+1) root:TaskNameW
    else
        redimension /N=(numberOfWaiterG+1) root:endtimeW
        redimension /N=(numberOfWaiterG+1) root:typeW
        redimension /N=(numberOfWaiterG+1) root:TaskNameW
    endif
       
    wave endtimeW = root:endtimeW
    wave typeW = root:typeW
    wave/T TaskNameW = root:TaskNameW
   
   
    TaskNameW[numberOfWaiterG] = TaskName
    typeW[numberOfWaiterG] = type
    endtimeW[numberOfWaiterG] = datetime+timeout
   
    numberOfWaiterG += 1
    printf "Waiting task number %g\r" , numberOfWaiterG
   
    //string WaitingTaskString = "waiterNum" + num2str(numberOfWaiterG)
    string WaitingTaskString = "waiter"
   
    if(numberOfWaiterG ==1)
        CtrlNamedBackground $WaitingTaskString,period=60,proc=waittaskUnified
        CtrlNamedBackground $WaitingTaskString, start
    endif
End

Function stopwaitUnified(ii)
    variable ii
   
    NVar numberOfWaiterG = root:numberOfWaiter
   
    wave endtimeW = root:endtimeW
    wave typeW = root:typeW
    wave/T TaskNameW = root:TaskNameW
   
    printf "Removed waiting Task number %g, with endtime %s, type %g and task %s\r" , (ii+1), (Secs2Time((endtimeW[ii]),3)), typeW[ii], TaskNameW[ii]
   
    //printf "%g. Alarm is on %s at %s\r", (ii+1),(Secs2Date((endtimeW[ii]),-1)), (Secs2Time((endtimeW[ii]),3))
   
    //string WaitingTaskString = "waiterNum" + num2str(numberOfWaiterG)
    string WaitingTaskString = "waiter"
   
    if(numberOfWaiterG <= 1)
   
        ctrlnamedbackground $WaitingTaskString,stop=1
        //killvariables root:endtime
        killwaves/Z endtimeW, typeW, TaskNameW
        numberOfWaiterG -= 1
        print "All Tasks done"
    else
        DeletePoints (ii), 1, endtimeW, typeW, TaskNameW
        numberOfWaiterG -= 1
    endif
   
End
 


//waitStatusPlusTimeLeft

Function waitStatusPlusTimeLeft()
   
   
    ctrlnamedbackground waiter,status
    if(numberbykey("RUN",S_info) != 0)
       
        NVar numberOfWaiterG = root:numberOfWaiter
       
        wave endtimeW = root:endtimeW
        wave typeW = root:typeW
        wave/T TaskNameW = root:TaskNameW
       
        printf "%g waiting task running\r" , (numberOfWaiterG)
        variable ii
        for(ii = 0; ii < numberOfWaiterG; ii += 1)
           
            variable Timeleft
           
            Timeleft = endtimeW[ii] - datetime
            printf "%g. Alarm is on %s at %s\r", (ii+1),(Secs2Date((endtimeW[ii]),-1)), (Secs2Time((endtimeW[ii]),3))
            printf "time for Alarm %g left %s\r",(ii+1),  (Secs2Time(Timeleft, 5 ))
        endfor
    else
        print "No timer running"
    endif  
   
    return numberbykey("RUN",S_info)
End

//unified wait task

Function waittaskUnified(s)
    STRUCT WMBackgroundStruct &s
   
    NVar numberOfWaiterG = root:numberOfWaiter
   
    wave endtimeW = root:endtimeW
    wave typeW = root:typeW
    wave/T TaskNameW = root:TaskNameW
   
    variable ii
   
    for(ii = 0; ii < numberOfWaiterG; ii += 1)
        string executeString
        sprintf executeString, "%s" ,TaskNameW[ii]
        if(datetime > endtimeW[ii])
            if(typeW[ii] == 1)
                ExecuteScriptText executeString
            else
                execute executeString
            endif
            stopwaitUnified(ii)
            //DeletePoints (ii), 1, endtimeW, typeW, TaskNameW
            //numberOfWaiterG -= 1
            //stopwait()
            //return 1
        endif
    endfor
    //print s
    return 0
End