Cycling is a great way to stay fit and healthy, and is cheap way to travel, but what if you don't know your way around?
A computer company in Japan has come up with a solution. It's a small unit that plugs into an iPhone and fits onto your cycle helmet with a display screen that can be flipped in front of one of your eyes - just like the HUD (or heads-up display) that fighter pilots use in planes.
The Unit makes use of the iPhones compass feature, which spins the map around to show which direction you are facing. The system uses small magnetometers (that measure the direction of the Earth's magnetic field) and GPS (Global Positioning System). However, the developers warn people that you shouldn't use it while riding around, in case you crash!
Have a look at a video of the unit in action at:
http://www.telegraph.co.uk/technology/apple/6251086/iPhone-cycling-app-heads-up-display-shows-map-while-riding.html