Accurate pedometer

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I bought a pedometer a few days ago to get an idea of how far I walked in a
day, with the intention of monitoring my daily activity. (E.g. search for
"10,000 steps" on google.)

I've been through three pedometers in the past week and these things really
don't work very well. The count is derived from a little pendulum that
swings back and forth on a spring. Switch debounce and sensitivity are major
problems with these pendulum based units, and I'm not aware of anything else
out there that tackles the job in a different way.

I've been wondering what might be a better way to make a pedometer, and also
if there is a way to do it with no moving parts.

My first thought was to put a sensor in each shoe, but then you'd have to
run wires between the two shoes, which is silly, or use RF. C'mon, "Blue
Tooth walking shoes"? I think that's going a little too far.

A reasonably reliable pedometer, no moving parts. Any suggestions?

Mike




Re: Accurate pedometer
Maybe a pressure sensor or piezo??



Re: Accurate pedometer

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Yes, and why would you need to monitor both shoes?
Presumably where one leg goes, the other is sure to follow shortly. Max
error = 1 pace.



Re: Accurate pedometer

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My pedometer goes off when I move around in my chair, etc. My thought was to
see if one was walking by measuring the time between footsteps to see if a
person is actually walking.

A piezo in the shoe? Maybe two: one in the back and one in the front to
determine whether a person is walking vs. having just put his feet up on the
desk.

Mike





Re: Accurate pedometer
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to
the

What about a magnet in one shoe and a coil and electronics in the other ?
Seems to me that moving your feet around while in a chair produces far less
steep signals than two feet passing eachother at high speed. Maybe two coils
in the shoe, to detect motion in one direction.

Meindert



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I think you should be able to set the threshold on a pressure sensor such
that it would only trigger the counter on Force >= 1/2 standing weight such
that sitting or pushing on the gas pedal wouldn't count.

Bob

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the



Re: Accurate pedometer

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Children's shoes with built-in piezos and LEDs have been available for
several years now - they flash the LED whenever the child takes a step.  It
should be relatively simple to buy a pair and gut the sensors.

Kelly



Re: Accurate pedometer

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It

Or not even that. Piezos are really easy to use.

The thing is that I was hoping that I had found a problem that needed
solving: "the world needs a cheap, accurate pedometer". It sounds like a lot
of people have already beat me to it! However, all is not lost. I was at the
gym tonight thinking about the applications of accelerometers and
pedometers.

Mike



Re: Accurate pedometer

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  Pedometers are by their very nature vague measuring devices, since they only
count steps, not distance.  Depends on the application I suppose.  If distance
accuracy is of at least some importance, then a pedometer is NOT the way to go.

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  You'd be hard pressed to get something with no moving parts, but I suppose
you mean "parts that don't move very much"- because a true no moving parts
solution (GPS?) would be too expensive.

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  I'm always in favour of a wired solution rather than wireless for
reliability, but owing to the inconvenience, in this case I'd say no.

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  Has anyone tried an accelerometer on the vertical axis, checking for the
shock that occurs when your foot hits the ground?  It would require some signal
conditioning, and possibly some smarts on measuring the peak acceleration all
the while dynamically changing the sensitivity to cater for different walkers?

  All of this should be doable with a single chip micro, so there wouldn't be
stupid amounts of hardware.

--
Linux Registered User # 302622                         <http://counter.li.org


Re: Accurate pedometer
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Depends on what you're trying to measure.

You could use GPS to measure diatsnce traversed. That wouldn't show
all the walking you do around the home/office.

You could count footsteps (which is what most try to do). That gives you
credit for stepping in place.

You could measure distance moved by each foot relative to the other.
That ignores stepping in place, but gives credit for laps and treadmills.
Measure it using elastic between the feet.



--
    mac the naf

Re: Accurate pedometer
On Fri, 7 Nov 2003 12:44:02 -0800, "Mike Turco"

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Get a GPS :-)

--
Al Balmer
Balmer Consulting
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Re: Accurate pedometer
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A GPS-pedometer wouldn't be much use for walking in the woods (under
dense trees), walking indoors (e.g. a shopping mall), or walking on a
moving platform (like a cruise ship).

--
Joe
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GPS Doesn't work under trees?  I dod not know that.



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Depends a bit on the quality of the GPS. I know mine doesn't. (HandyGPS Pro
on a Visor)

Meindert



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Pro

The GPS my friend uses for work works under trees. The only trouble is it's
got an 18 inch diameter antenna and is held over his head attached to a pole
on a backpack so it's a little heavy. Not exactly a very convenient
pedometer but very accurate if you are a cartographer.

Peter



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By the way, that should be attributed to me.

To continue this OT thread, there are trees and there are TREES.  (I
live in the Northwest U.S. where the 100+ foot pines, firs, larch, etc.
do a very effective job of signal attenuation at 1.6 GHz).

--
Joe
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Re: Accurate pedometer
On Mon, 10 Nov 2003 14:08:55 -0800, Joe Dubner

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You might be surprised, actually. A good GPS will work in most
buildings, and even do well in fairly dense tree cover. In the woods,
a conventional pedometer wouldn't have much practical use either.

Anyway, I like some of the other ideas presented here better.

--
Al Balmer
Balmer Consulting
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Re: Accurate pedometer

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Not sure how you quantify a "good" one.  My Garmin GPS-196 isn't a "bad"
one but doesn't report any satellite signal strength in my aircraft
hangar or basement.  Nothing indoors at work either.  Neither do my
older Lowrance or my newer Magellan "hiker's GPS" units.

One particular problem with pine and fir trees is that their needles can
be about a half-wavelength long at the frequency of interest.  The GPS
signal is attenuated very effectively.

The practical use of a conventional (or otherwise) pedometer in the
woods would depend on the woods.  Again, here in the northwest, we have
"woods" (forests) with trails that go on for miles.

--
Joe
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Re: Accurate pedometer
On Tue, 11 Nov 2003 14:33:32 -0800, Joe Dubner

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I have a Garmin StreetPilot. I'm sure I could find places where it
doesn't work (the bottom of Oak Creek Canyon, AZ is one) but I've used
it in fairly dense woods, and inside many buildings (including
shopping malls), so I still think the original statement was too broad
a generalization.

--
Al Balmer
Balmer Consulting
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Re: Accurate pedometer

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Even if you would get some usable signal levels inside a building
through reflections from nearby buildings or sneaking through some air
conditioning ducts, the path distance from the satellite to the
receiver would be much longer than when the receiver is outside.

Since the receiver location is calculated from the trigonometric
distances from each satellite (at known positions), most likely the
calculated location would be 100 m below the ground and if it happens
to be near ground level, quite a large number of meters away from the
true position. If some satellites are received (nearly) direct and
some trough long reflective paths, the position will be biased in some
direction.

Worst of all, when moving in such an environment, the path lengths
will constantly vary and hence, the calculated position will jump
wildly. Trying to calculate a speed from such position reports would
be quite meaningless, since the speed would vary much faster than a
pedestrian can walk :-).

Of course some receivers will employ various kinds of filters (Kalman
etc.) to reduce the position oscillation, but on the other hand, they
will respond slowly when the users gets out of a building with a lot
of bad readings in the filter.

Paul
    

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