Many people use the conditional formatting features of Excel to draw attention to specific values or areas of their worksheets. For instance, a cell might be formatted so that its contents are displayed in red or in boldface if above or below a certain threshold.

What is missing, however, is a way to make the contents of a cell flash, or blink on and off. For such a feat, you are left to your own devices and the miracle of macros. By utilizing these tools, you can make cells blink by first designing a special style for the blinking cells, and then running a simple macro.

To create the special style, follow these steps if you are using Excel 2007:

1. Select the cell that you want to flash on and off.
2. Make sure the Home tab is displayed on the ribbon.
3. In the Styles group, click Cell Styles. Excel displays a drop-down selections of pre-defined styles.
4. Choose New Cell Style. Excel displays the Style dialog box. (See Figure 1.)



Figure 1. The Style dialog box in Excel 2007.

5. Using the controls in the dialog box, modify any attributes for the style, as you desire.
6. Click on OK.

If you are using an older version of Excel, follow these steps instead:

1. Select the cell that you want to flash on and off.
2. Choose Style from the Format menu. Excel displays the Style dialog box. (See Figure 2.)



Figure 2. The Style dialog box.

3. In the Style Name box, enter a new style name, such as Flashing.
4. Using the controls in the dialog box, modify any attributes for the style, as you desire.
5. Click on OK.

You can now apply the style to any other cells you desire in your workbook. Now create the macros (there are two of them), as follows:

Dim NextTime As Date

Sub StartFlash()
    NextTime = Now + TimeValue("00:00:01")
    With ActiveWorkbook.Styles("Flashing").Font
        If .ColorIndex = xlAutomatic Then .ColorIndex = 3
        .ColorIndex = 5 - .ColorIndex
    End With
    Application.OnTime NextTime, "StartFlash"
End Sub

Sub StopFlash()
    Application.OnTime NextTime, "StartFlash", schedule:=False
    ActiveWorkbook.Styles("Flashing").Font.ColorIndex = xlAutomatic
End Sub

To start the items flashing, simply run StartFlash. The cells formatted with the Flashing style will alternate between red and white text approximately once a second. When you want to turn the flashing off, simply run the StopFlash macro.

There is one important thing to note about this macro: the variable NextTime is declared outside of the actual procedure in which it is used. This is done so that NextTime maintains its value from one invocation of StartFlash to the next.