Countdown Timer for Excel

Hi, I have a spreadsheet (attached) that populates data 5 times per second from an external source using COM. Data is populated in various places but the relevant part is range O5-O45 on sheet W1. I want a timer to start automatically at 3 seconds and run down each time two or more values in that range are equal to or less than 2, ignoring blank cells. Some more details: 1. if on a subsequent refresh of the data two or more values are again equal to or less than 2 the countdown should restart at 3, even if the previous countdown has not reached 0; 2. on reaching 0 the cell should return to empty; 3. the timer should appear in cell AF5 of sheet W1; 4. there is other code in the spreadsheet and it will need to run alongside that without conflict. It will also need to run alongside other spreadsheets containing VBA without conflict; Thanks