Computers and electronic devices will help you have more knowledge of how your ride went and where you traveled to.  Here at CYCLEWERX we carry a complete selection of computers and electronics.  The function of the computer is to identify; current speed, odometer, trip distance, 12/24 hr clock, elapsed time, average speed, maximum speed,  outside temperature, and in some cases cadence (how quickly in RPM's you are spinning the pedals.) 

Computers calculate your speed by use of a magnet attached to one of the spokes on a wheel and a corresponding magnetic switch mounted on the frame or fork of your bike to sense the magnet as it passes by the switch.  The frequency of the switch being "tripped" is sent to the head unit  where speed and distance is calculated and displayed.  A big decision to make when choosing a computer is whether you want it to be wired or wireless.  With a wired computer information is sent from the magnetic switch at the wheel to the head unit via a wire,  with wireless it is wireless. Wireless computers are generally preferred as they provide a cleaner looking application.   

Other electronic devices such as GPS help you know what roads you are currently on and what roads to take, most also will take you bake home.  Bicycle GPS devices are smaller versions of the ones you may use in your car.  One final feature many of these devices have is the ability to upload information they gathered on your ride to your computer.  This is a great way to log your activity and see improvements over time.