Have had a look through my files and here are some more I couldn't remember yesterday
(Note: "Files" = big pile of loose A4 sheets in a wire basket)
You are probably thinking of MEW no 201, which was 2 years ago, but this doesn't use a wiper motor.
My favourite is in MEW no 50, uses a wiper motor, have seen it in use.
One for a Naerok in nos 113/114, but doesn't use wiper motor (cheapo off ebay instead)
The most elegant solution is from Dave Machin in MEW nos 14/15.