A small function to convert decimal integer values to a binary string. The number of bits can be optionally specified but this will be increased if insufficient.

Public Function DecToBin(DeciValue As Long, Optional NoOfBits As Integer = 8) _
As String
'********************************************************************************
'* Name : DecToBin
'* Date : 2003
'* Author : Alex Etchells
'*********************************************************************************
  Dim i As Integer
  'make sure there are enough bits to contain the number
  Do While DeciValue > (2 ^ NoOfBits) - 1
    NoOfBits = NoOfBits + 8
  Loop
  DecToBin = vbNullString
  'build the string
  For i = 0 To (NoOfBits - 1)
      DecToBin = CStr((DeciValue And 2 ^ i) / 2 ^ i) & DecToBin
  Next i
End Function