Quick script that will allow you to pipe each char in a String into the PowerShell pipeline.
param ( [string]$toPipe )
for ( $i = 0; $i -lt $toPipe.Length; $i++ )
Alternatively you can do this by using the ToCharArray method. However this will create a new array in memory and if you have a large string that will be fairly expensive. The above method will do it the PowerShell way.