After having little success using a $250 Timex Bodylink GPS watch (see review) in Manhattan, I decided to try this $15 pedometer. At first I was quite skeptical. However my tests showed the Sportline 340 Pedometer having astounding repeatability (better than 1%) and accuracy.

Most pedometers, including this one, are very basic instruments. Inside the device, there is a balanced weight that is very sensitive to vertical motion. When clipped to your belt, it increments the counter as you step driven by the translation of one side of your waist.

In order to test and calibrate the Sportline 340 Pedometer, I walked a very straight stretch of six Manhattan blocks. In the first group of tests, there were few sidewalk obstacles and minimal pedestrian traffic that impeded my movements. In order to be moderately scientific, I was certain to start and stop on the proper side of the street so the distance included exactly six stretches of cross street and six stretches of sidewalk.

After four trips of walking the same path, my step counter showed an amazingly small range of 588 to 594 steps. When one considers the variables imposed, such as not always being able to walk completely straight, the results are even more impressive. As you can see from the data below, the accuracy was quite amazing. The difference from the mean never exceeded 1%. Given the simplicity of the pedometer, I didn't expect this level of repeatability. Moreover, I didn't expect my stride length to be so uniform.

My hypothesis was that the exceptional accuracy may have been fostered, in part, by the shoes I was wearing. The Kenneth Cole Building Block shoes (see review) have very heavy soles and large heals. These may insure that the impact is harsh enough to always trigger the movement of the weight.

On a second grouping of tests, I walked precisely the same path wearing my New Balance 620 cross trainers (see review). The conditions were not the same as the first group due to far more pedestrian traffic and other obstacles, which made it very difficult to walk in a straight line. In fact, one test had to be scrapped as I was nearly run over by a taxi. As you can see below, the second group produced a step count about 2% greater than the first group. Yet this was probably due to the unavoidable path changes.

Considering that the pedometer is only calibrated in whole inches, the accuracy truly limited by the precision of the calibration settings. This means there is no difference in the two calibrations as both stride lengths would round to 32 inches.

For the price, the Sportline 340 pedometer is an excellent piece of fitness equipment. If you enjoy low-impact exercise by walking, consider this device as an excellent tool for tracking your efforts.

Pros
Inexpensive
Light
Accurate

Cons
Lack of speed, time or other measurements
Requires user to look down while tilting the device upward
Possible inaccuracy caused by movement other than walking
Needs greater calibration precision



TEST DATA

Experimental conditions:
1) NYC Avenue N/S: Amsterdam from 73rd to 79th
2) Measured distance on MS Streets and Trips 2005: .301 miles/1589 feet
3) Calculated distance based on NYC grid: .300 miles/1584 feet


Group1 - Wearing Kenneth Cole Building Block Shoes
________steps____diff from mean____calculated stride length
Test 1____592____0.04%________32.22
Test 2____593____0.21%________32.16
Test 3____594____0.38%________32.11
Test 4____588____-0.63%________32.43
Average____591.8____________32.23
Std Dev____2.6

Group2 - Wearing New Balance 620 Cross trainers
________steps____diff from mean____calculated stride length
Test 1____597____-0.75%________31.95
Test 2____614____2.08%________31.06
Test 3____595____-1.08%________32.05
Test 4____600____-0.25%________31.79
Average____601.5____________31.71
Std Dev____8.6


5 stars

I gave this pedometer one star because it is not for anyone who wants to use it straight off of the shelf. This pedometer can work if you do not mind working on it. It has problems that need modification.

The top of the clip on this pedometer pushes against the body, making the vertical angle 20 degrees or more off of plumb. That means the weighted arm inside drags on the circuit board and does not move freely. Remove the factory clip and the tabs that hold it. Add some adhesive Velchro to the back of the case. Make a fabric band for your ankle. Attach the ends to each other with Velchro. Put a strip of Velchro on the outside of the band for attaching the pedometer to the band. I get accurate readings with this pedometer when it is attached to the inside of my right ankle. I got inconsistent readings with it on my waistline.

The hair spring that returns the weighted arm to its upright position weakened considerably after about ten miles and the pedometer drastically undercounted. I opened the pedometer and added a strut to brace the spring. The strut is made of thin brass. Aluminum from a soda can would work, too. I made a "V" in one end of the strut to hold the spring. I pushed lightly against the spring from the left side, drilled a hole in the brass, and anchored the strut to a screw on the lower left part of the circuit board. The strut angles up just slightly from the screw that anchors it. I now have quite a few miles on the pedometer. (I have a theory the spring weakened because its solder joint to the circuit board may have broken slightly and allowed the spring to twist freely.)

Several times the pedometer reset itself to "0" for no apparent reason. I know nothing pushed on the reset button. One incident was while it was going through the scanner at airport security. Once it reset while I was walking. Twice it reset while I was napping on the sofa. I am thinking a charge of static electricity overwhelmed the circuit, but I do not know. Static electricity from too many synthetic fabrics can be a problem with more expensive pedometers, too.

This pedometer uses a counter circuit. If someone needs an inexpensive electronic counter, connect a wire to the weighted arm and another wire to the coiled spring it contacts. Connect a button switch to the two wires. Freeze the weighted arm in place with hot glue. 1 star

Although this pedometer is cleanly designed with its buttons easy to use and a clear digital display, it is worthless because it is inaccurate. I left it on for several hours while walking around doing normal tasks, and it registered only a few steps. I had clipped in on my belt just as the instructions described.

I think the problem is that this pedometer is just not sensitive enough. If you are walking normally, it doesn't register the steps. If you are pounding the pavement, it does better. 1 star

Great on accuracy (as long as it is level -- like most pedometers). Only 3 stars, though, because the belt clip is not a full belt clip but a mere spring clip. Mine came off twice. It would have probably come off more than that except for the fact that I have not recovered it yet.

For only a few dollars, it is well worth it; HOWEVER, be wary of your delivery charges. I was charged from Amazon's third-party seller almost twice the cost of the pedometer for delivery. (It required no more than a small padded envelope and was sent via regular US mail.)
3 stars

When I first bought this, I thought this was a cheap product. However, then I read the directions!! I took several distance measurements of my strides (the "how too's" are in the directions) and then programed the stride lenght into the pedometer and it was accurate with in about 30 to 40 steps. I'm sure there are better mods, but this one is simple & small & pretty accurate in my opinion! Especailly for what you pay!
(I would recommend buying the used ones in "new" or "like new" condition - or somewhere that you can return them if you don't find it easy or accurate. Based on the other reviews, I think people just don't program them right.) Check out http://ihatefat.blogspot.com/2005/03/blame-it-on-rain.html for information on calculating your stride lenght.
I hope this helps! 4 stars