Implement search box into current worksheet with macro - excel

Question

My macro currently works by pressing CTRL+F to open the search box which searches either REF1 or REF2. If the information is found, it copies over to the next cell basically to show it's there. If the information is not found, it pastes the data searched for in cell L4 so a label can be printed.
What I'm trying to do:
Remove the CTRL+F and basically run from a cell (let's say cell L18). However, when scanned the scanner basically types in the numbers then presses enter/return.
I was wondering, would it be possible to make it run like this.
Select cell L18 then keep scanning until either:
A) The list is done - nothing is missing
B) If REF1/REF2 doesn't match, pastes that data into cell L4 for a label to be printing.
(Current version using CTRL+F): http://oi39.tinypic.com/mima9x.jpg
(Example of what I need): http://oi42.tinypic.com/24fiwt1.jpg
Current macro:
Sub Extra_Missing_Item() Application.ScreenUpdating = False
Dim rangeToSearch As Range
With Sheets(1)
Set rangeToSearch = .Range("A2:B" & .Range("A" & .Rows.Count).End(xlUp).Row)
End With
Dim searchAmount As String
searchAmount = InputBox("Scan the REF1 or REF2:")
Dim cell As Range
Set cell = rangeToSearch.Find(searchAmount, LookIn:=xlValues)
With Sheets(1)
If Not cell Is Nothing Then
.Range("E" & cell.Row & ":G" & cell.Row).Value = _
.Range("A" & cell.Row & ":C" & cell.Row).Value
Else
MsgBox "REF1/REF2: " & searchAmount & " shouldn't be here"
.Range("L4").Value = searchAmount
Range("L9").Select
End If
End With
Application.ScreenUpdating = True
End Sub

Answer 1

I think I understand what you need. This macro calls each time any cell on the sheet changed (but if changed cell is not L18, macro do nothing):
Private Sub Worksheet_Change(ByVal Target As Range)
If Application.Intersect(Target, Range("L18")) Is Nothing Then
Exit Sub
End If
Dim rangeToSearch As Range
Dim searchAmount As String
Dim cell As Range
Application.ScreenUpdating = False
Application.EnableEvents = False
Set rangeToSearch = Range("A2:B" & Range("A" & Rows.Count).End(xlUp).Row)
searchAmount = Target.value
Set cell = rangeToSearch.Find(searchAmount, LookIn:=xlValues)
If Not cell Is Nothing Then
Range("E" & cell.Row & ":G" & cell.Row).value = _
Range("A" & cell.Row & ":C" & cell.Row).value
Else
MsgBox "REF1/REF2: " & searchAmount & " shouldn't be here"
Range("L4").value = searchAmount
End If
Range("L18").Select
Application.EnableEvents = True
Application.ScreenUpdating = True
End Sub
Put this macro in the Sheet module (coresponding to the sheet where your data is):