A pedometer (also known as a Tomish-meter, perhaps after the alleged inventor of a successful device, Thomas Jefferson ) or step counter is a device, in modern times usually portable and electronic or electromechanical, that counts each step a person takes by detecting the motion of their hips. Because the distance of each person's step varies, an informal calibration performed by the user is required if the distance in yards or miles is desired.

Used originally by sports and physical fitness enthusiasts, pedometers are now becoming popular as an everyday exercise measurer and motivator. Often worn on the belt and kept on all day, it can record how many steps the wearer has walked that day, and thus the kilometres/miles (distance = number of steps x step length). Some pedometers will also erroneously record movements other than walking, such as bending to tie one's shoes, or road bumps incurred while riding a vehicle, though the most advanced devices record fewer of these 'false steps'. Step counters can give encouragement to compete with oneself in getting fit and losing weight. A total of per day, equivalent to , is recommended by some to be the benchmark for an active lifestyle, although this point is debated among experts. Step counters are being integrated into an increasing number of portable consumer electronic devices such as music players and mobile phones.

Recently, exercise enthusiasts have observed that an advanced Global Positioning Satellite (GPS) receiver (GPSr) with an odometer mode serves as a very accurate pedometer for outdoor activities. While not truly counting steps (no pendulum is involved) an advanced GPSr odometer can reveal the accurate distance traveled to within 1/100th of a mile (depending on the model, perhaps 1/1000th of a mile). 1/1000th of a mile is approximately the distance of a single pace or 2 steps.

The modern definition of the international mile traces back to the Roman military method of keeping track of how far a soldier had traveled on foot. The Latin "mille passus" is literally "a thousand paces" where 1 pace = 2 steps. The international mile (5,280 US feet) is somewhat longer than the original Roman mile (4,854 US feet). As with the mile, the definition of "foot" has changed many times.

Usage

Pedometers can be a motivation tool for people wanting to increase their physical activity. One way is with interactive mapping websites like http://www.stepsout.com that allow users to track their progress on a virtual map. Pedometers have been shown in clinical studies to increase physical activity, and reduce blood pressure levels and Body Mass Index. A study published in the Journal of The American Medical Association Nov. 2007 concluded, “The results suggest that the use of a pedometer is associated with significant increases in physical activity and significant decreases in body mass index and blood pressure.”

History

The Romans used an hodometer calibrated to steps to measure distances for military and civil purposes, although technically this is not a step counter. Leonardo Da Vinci envisioned a mechanical pedometer as a device with military applications.

The modern all-mechanical pedometer was introduced later to the Americans by Thomas Jefferson as noted briefly in the Article "Thomas Jefferson, Abraham Lincoln, Louis Brandeis and the Mystery of the Universe" by Mark L. Wolf, published by Boston University Journal of Science & Technology Law, vol. 1, May 1995 (downloadable from http://www.bu.edu/law/scitech/volume1/WOLF.PDF). Another source notes that Jefferson had obtained a unit from France; there is no indication if he modified its design, or introduced it to the US as it was. http://canada.better-vacations.info/tag/bell-canada-411-ontario Although this pedometer is widely attributed to Mr. Jefferson, proof is difficult to obtain as he never applied for any patents on any of his inventions. See "AN OVERVIEW OF JEFFERSON'S INVENTIONS" at http://cti.itc.virginia.edu/~meg3c/classes/tcc313/200Rprojs/jefferson_invent/invent.html

In more recent times the device was popularised in Japan by Y. Hatano as the manpo-meter. http://www.procor.org/discussion/displaymsg.asp?ref=2266&cate=ProCOR+Dialogue http://canada.better-vacations.info/tag/bell-canada-411-ontario

Technology

The technology for a pedometer includes a mechanical sensor and software to count steps. Early forms used a mechanical switch to detect steps together with a simple counter. If one shakes these devices, one hears a lead ball sliding back and forth, or a pendulum striking stops as it swings. Today advanced step counters rely on MEMS inertial sensors and sophisticated software to detect steps. These MEMS sensors have either 1-, 2- or 3-axis detection of acceleration. The use of MEMS inertial sensors permits more accurate detection of steps and fewer false positives. The software technology used to interpret the output of the inertial sensor and "make sense of accurate steps" varies widely. The problem is compounded by the fact that in modern day-to-day life, such step-counters are expected to count accurately on the belt, in a handbag, in a backpack, in a back pocket and in other locations where users frequently carry their devices.

Accuracy

The accuracy of step counters varies widely between devices. Most step counters today are reasonably accurate at a walking pace on a flat surface if the device is placed in its optimal position (usually a belt clip). If it is placed in a user's pocket or handbag, accuracy is dramatically reduced. Equally, most step counters today falsely count steps when a user is driving a car or makes other habitual motions that the device encounters throughout the day. This error accumalates for users with moderate commutes to work. Accuracy also depends on the step-length the user enters.

Best pedometers are accurate to within +/- 5% error.

Integration in Personal Electronic Devices

Nike+iPod

Apple and Nike, Inc. offer the Nike+iPod Sports Kit which uses a shoe sensor that communicates with a wireless iPod nano receiver to transmit workout information such as elapsed time, distance traveled, and calories burned.

NTT DoCoMo Fujitsu Pedometer Phone

This is the first integrated phone with a pedometer that works 24 by 7 and counts step like an Omron pedometer. The sensor is made by ADI. This handset was introduced in Japan in 2004 and has sold over 3 million units.

Nokia 5500 Sports Phone

The Nokia 5500 Sports Phone uses an embedded 3 axis MEMS inertial sensor to detect the steps a user takes. The pedometer application tracks steps taken, time elapsed and distance traveled. However the application cannot run continuously as it drains the phone's battery and is therefore of limited use.

Sony Ericsson W710 walkman phone, W580 walkman phone

The Sony Ericsson W710 and W580 walkman phones use embedded 2 axis MEMS inertial sensors to detect the steps a user takes. The W710 is a clamshell phone and displays the user's steps on the external display. The W710 must be closed in order for it to count steps. When the step counter is activated, it counts detected steps during the day, and at midnight it stores the counter in a day-by-day history and resets it to zero.

Future Solution

To date, the Omron pedometer uses a second generation algorithm that is reasonably accurate clipped on a belt. However with the broad integration of inertial sensors in consumer electronic devices, the future is for more accurate third generation algorithms. Research is on-going.

External links

• Pedometers and Step Watching (About.com)
• How Does a Pedometer Work
• NPR report-Pedometer Fitness Fad Takes Off
• Google Maps Pedometer
• http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15529901&dopt=Abstract Pedometers and brief e-counseling: increasing physical activity for overweight adults.
• Pedometer article
• Guide to Buying the Best Pedometer

• Pedometer users walk farther

• Pedometer Information Sheet (Alberta Centre for Active Living)
• Watch Your Step: Pedometers and Physical Activity (Alberta Centre for Active Living)

References