The BBC has an article about a new type of goggles designed by an industrial design student named Katie Williams. They are called the “Inview Goggles” and they feature a small compass which tracks when you change direction in the pool. They can tell you how many laps you have swum and how long you have been swimming.
This strikes me as a good idea. Granted, they will need to make the electronics smaller than the current size (the size of a small stone) but I might consider looking into these once they get on the market, if they are not too expensive. It would be very useful in training to be able to concentrate more on stroke and form and less on how long I’ve been swimming.