Seems like it would take forever to tell you that it was 11:55. It would probably take 20 seconds and be totally disruptive. People would get used to me "zoning" while I count the vibrations. This is a bad interface


For this to be useful, the interface would have to be much quicker. Forget the hours, If I'm reminded of the time every 10 minutes, I can keep track of the hours. And forget the five minute increment -- that is too much.

Limit it to 10 minute intervals.

Then do something clever to make it quicker (like roman numerals)
Use one long vibration to indicate the hour (any hour). Then if short vibrations preceed the one long "hour" vibration, it means "of the hour", if the shorts come after the long, it would mean "after"

So, using - and . for long and short:
11:50 would be: . -
and 11:10 would be: - .
11:20: - . .

This would work much better.