Are We There Yet?
June 24, 2021
There’s a Keystone in every great invention.
Odometers and their Electronics
With the official start of summer comes vacation season. Like Chevy Chase in Summer Vacation, nothing beats the family road trip. Whether you are headed to the beach, the mountains or the Wally World, Americans from coast to coast will pile into the family car and pack the highways in route to summer sun and fun. Some of us will travel thousands of miles this summer in search of the perfect destination, and we can count the miles thanks to a little gadget called the odometer.
An odometer is an electronic, mechanical or electromechanical instrument used to measure distance. Marcus Vitruvius Pollio (Vitruvius), a Roman author, architect, and civil and military engineer during the 1st century BC first in a text written around 27 - 23 BC. However, many historians believe the actual inventor may have been Archimedes of Syracuse (287 BC – 212 BC) during the First Punic War. In his writings, Vitruvius describes an odometer constructed using a retrofitted 4-wheeled chariot. After each revolution, a pin on the axle turned a 400-tooth cogwheel. After 400 revolutions, another gear was activated to drop small rocks, one by one, into a box to track the completion of a Roman mile. The total distance traveled was measured by counting the number of rocks in the box.
The odometer was also independently invented in ancient China, potentially by the well-known inventor Zhang Heng (78 AD – 139 AD) of the Han Dynasty. Chinese texts in the 3rd century describe the mechanical li-recording drum carriage in detail. As one li was traveled (1,640 feet), a mechanical-driven wooden figure hit a drum, and when ten li was traversed, another wooden figure would strike a gong or a bell with its mechanical-operated arm.
Odometers for Wagons
Levinus Hulsius, a designer and dealer of scientific instruments, published an odometer for wagons and other horse-drawn vehicles in order to measure distances traveled. Benjamin Franklin, the first US Post Master General, built a simple odometer prototype in 1775 that he attached to his carriage to help measure the mileage of postal routes.
The modern odometer was developed in 1847 by Mormon pioneers William Clayton and Orson Pratt. Marketed as the Roadometer, the system of wooden cog wheels attached to a wagon wheel to count quarter-miles, half-miles, and whole miles. The system used two gears, where the first gear advanced the next gear one position when moved one complete revolution.
In 1895, Curtis Hussey Veeder invented the Cyclometer, a mechanical device that counted the number of rotations of a bicycle wheel. A flexible cable transmitted the number of wheel rotations to an analog odometer visible to the rider, which converted the wheel rotations into the number of miles traveled according to a predetermined formula.
In 1903, the first odometer was developed for automobiles. Invented by Arthur P. and Charles H. Warner of Beloit, Wisconsin, the device was patented as the Auto-Meter. Unlike its predecessors, the innovative Auto-Meter used a magnet attached to a rotating shaft to induce a magnetic pull upon a thin metal disk. Measuring this pull provided a more accurate measurement of both distance and speed information to automobile drivers in a single instrument. Trip odometers were soon introduced into vehicles as well. Unlike the odometer, a trip meter is reset at any point in a journey, making it possible to record the distance traveled in any particular journey or part of a journey. By 1925, odometers and trip meters were standard equipment on the vast majority of automobiles and motorcycles manufactured in the United States.
The digitization of odometers for automobiles, motorcycles, and bicycles phased out mechanical odometers in the early 2000s. Today, all odometers are electronic.