Accuracy issues with my Blaze

[StuartN]

I use my Blaze alone, without a smart phone or any GPS app.  I beleive my step counts are ok, but total distance is sometimes way off, for example, I drove my car 3.5 miles then walked the exact same path and the Blaze came up with 2.75 miles.  So today I tried different walking paces for a 1/2 mile walk and set the stride to 2.5 and 3.0.  The results were:

Steps           Stride           Blaze distance

812                2.5                 0.39

745                2.5                 0.34

1079              2.5                 0.51

743                3.0                 0.41

So without a GPS, all this Blaze is doing is multiplying steps by stride factor and dividing by 5280 (feet in a mile).  It really does not know the real distance you walk.  In the above tests, they all should have yielded the same 0.50 miles as that was the distance of the path.  So the longer you walk, the further off it gets.   Am I understanding this correctly?  Any suggestions?   Thanks.

[Rich_Laue]

@StuartN your correct in saying that the Blaze does not measure distance, and that it must be calculated.

So let's assume that you drove the car 3.5 miles and that it is correct, due to tire pressure and other things it most likely is off. 

As you noticed, as you change your pace your stride also changes.. Not changing the setting to match on Fitbit will give unreliable results. What is not clear is 2.5 refering to 2 feet 6 inches as in two and a half feet, or 2 feet 5 inches? 

I'm going to assume that the 3.5 mile walk was done at your normal place and suggest using that for an initial setup.. Take the steps walked during this 3.5 miles and figure out the stride. Using a fictitious 2.5 or 3.0 wont give any usable data. 

You want to start by doing all testing at your normal pace.

Steps           Stride           Blaze distance

812                2.5                 0.39 : real stride 3'3" 

745                2.5                 0.34 : real stride 3'6"

1079              2.5                 0.51 : real stride 2'5.35"

743                3.0                 0.41 : real stride 3'7"

In each case your stride setting was not set to your true stride and therefore the miles reported will be off by the same percentage. 

So what is a person to do? 

This is what I did, having a certified 5k run near me, this is what I used it's 3.1 miles long. I did this walk 5 times on 5 days, took the total miles of 15.5 and divided it by the total steps of 11530. This gives me an average stride of 2'6.23".

I now find the distances walked very close. 

[StuartN]

thanks for the reply, it is true I set an artificial stride rate, but one will not know their true stride until after the walk is over and calculates it, so I guess I need to determine a decent average based on walking at work, exercising, at home, supermarket, etc, each type of work will have a different stride factor.  It does not seem reasonable to keep changing the stride before each type of walk I plan on doing.  At least, I figured out how it works, originally I thought it was more sophisticated taking into account amount of time of walk and I actually thought it measured distanced.  Oh well, live and learn, thanks for the info.

[Rich_Laue]

I don't worry about daily axtivity, it's just too in consistant in both stride and step count,. Something's won't give me steps, carrying a big package, pushing a cart, while at other times false steps are recorded, clap your hands, jump up and down, etc. 

For me I want my walls measured correctly, so that is what the stride is set for.