A cyclocomputer, cycle computer, cycling computer or cyclometer is a device mounted on a bicycle that calculates and displays trip information, similar to the instruments in the dashboard of a car. The computer with display, or head unit, usually is attached to the handlebar for easy viewing. Some GPS watches can also be used as display. History In 1895, Curtis H. Veeder invented the Cyclometer. The Cyclometer was a simple mechanical device that counted the number of rotations of a bicycle wheel. A cable transmitted the number of rotations of the wheel to an analog odometer visible to the rider, which converted the wheel rotations into the number of miles traveled according to a predetermined formula. After founding the Veeder Manufacturing Company, Veeder promoted the Cyclometer with the slogan, It's Nice to Know How Far You Go. The Cyclometer's success led to many other competing types of mechanical computing devices. Eventually, cyclometers were developed that could measure speed as well as distance traveled. Basic operation The head A basic cyclocomputer with a wheel speed sensor may display the current speed, average speed, maximum speed, trip distance, trip time, total distance traveled, and the current time. More advanced models with additional sensors and storage may display and record altitude, incline (inclinometer), heart rate, power output (measured in watt) and temperature as well as offer additional functions such as pedaling cadence, a stopwatch and even GPS navigation and video data overlay synchronization. They have become useful accessories in bicycling as a sport and as a recreational activity. The display is usually implemented with a liquid crystal display, and it may show one or more values at once. Many current models display one value, such as current speed, with large numbers, and another number that the user may select, such as time, distance, average speed, etc., with small numbers. The head usually has one or more buttons that the user can push to switch the value(s) displayed, reset values such as time and trip distance, calibrate the unit, and on some units, turn on a back light for the display. Most displays are navigated by pressing buttons and high-end models use a capacitive touch screen to navigate screens and maps. The wheel sensor The older, traditional sensors have a magnet attached to a spoke of either the front or rear wheel. A sensor based either on the Hall effect, or on a magnetic