Most of the presented solutions use Application.Wait, which does not take in account the time (miliseconds) already elapsed since the currend second count started, so they have an intrinsic imprecision of up to 1 second.
The Timer approach is the best solution, but you have to take in account the reset at midnight, so here is a very precise Sleep method using Timer:
'You can use integer (1 for 1 second) or single (1.5 for 1 and a half second)
Public Sub Sleep(vSeconds As Variant)
Dim t0 As Single, t1 As Single
t0 = Timer
Do
t1 = Timer
If t1 < t0 Then t1 = t1 + 86400 'Timer overflows at midnight
DoEvents 'optional, to avoid excel freeze while sleeping
Loop Until t1 - t0 >= vSeconds
End Sub
USE THIS TO TEST ANY SLEEP FUNCTION: (open debug Immediate window: CTRL+G)
Sub testSleep()
t0 = Timer
Debug.Print "Time before sleep:"; t0 'Timer format is in seconds since midnight
Sleep (1.5)
Debug.Print "Time after sleep:"; Timer
Debug.Print "Slept for:"; Timer - t0; "seconds"
End Sub