[dorkbotpdx-blabber] Fwd: [freegeek-social] Bike Counter for WNBR -- ideas? volunteers?

[dan p]

yep, get it.

if instead of the rubber tube, you had a series/matrix of LASERs (caps as it
is an acronym) maybe in more than one color, maybe some sort of series of
perpendicular to the path of travel, and a few at several angles. They could
be positioned at several heights (low to see tires, four breaks per bike if
more than a couple inches above the ground, roughly torso height? you could
look for min/max beam interupt to see if your seeing two signals from one
person (arm then torso) or if someone has big tires then you would see two
big beam breaks instead of 4 shorter ones.

The multi colored LASERs would add to be party like feeling and you wouldn't
need to worry about sticker pattern recognition, or nipple recognition, or
tripping people on hoses (you may have to worry about blinding people with
multiple lasers pointed at them, but life is a series of tradeoffs).

just more random thoughts, maybe this one is a bit more reality based.


On 5/29/08, Frank Canaan <fcanaan at gmail.com> wrote:
>
> Chances are a cattle chute setup will make almost all of these ideas easier
> to implement... Funneling people into a thinner stream will make things more
> accurate.
>
>  On Wed, May 28, 2008 at 7:40 PM, <subbies at redheadedstepchild.org> wrote:
>
>> wellllll, you could even throw in the last
>> colored-sticker-on-helmet-for-Processing in tandem with my idea
>> (making it colored sticker on helmet with number) and thereby try *three*
>> out all at once.
>> -Alexis
>>
>> + --------
>>   redheadedstepchild.org
>>        ------- +
>>
>> On Wed, 28 May 2008, Donald Delmar Davis wrote:
>>
>> ::How about we pick 2 methods (ground sensor image processing) with
>> alexis's
>>  ::sticker idea as a control mechanism and implement them.
>> ::
>> ::Document the results.
>> ::
>> ::
>> ::Management. We need some management here.....
>> ::
>> :::)
>> ::
>> ::On May 28, 2008, at 10:23 AM, Mykle Hansen wrote:
>> ::
>> ::>
>> ::> On May 28, 2008, at 7:42 AM, Jason Plumb wrote:
>> ::>
>> ::> > I've always wondered how those things work and what the response
>> rate is
>> ::> > like.  Do they really just give an on/off or are they using a
>> summing
>> ::> > pressure system of some kind?  Are they *really* capable of
>> detecting when
>> ::> > two cars/bikes pass over very *very* close together?  Just given the
>> ::> > number of cars on the road, isn't there a pretty high statistical
>> ::> > probability that two will hit in the same millisecond (or
>> lower)...so how
>> ::> > do *they* handle it?
>> ::>
>> ::> i don't know exactly how, but here is a paper from 2002, in which
>> ::> NZ traffic engineers tested some of the tube devices on the market
>> ::> for counting both cars and bikes:
>> ::>
>> ::>   http://www.ipenz.org.nz/ipenztg/papers/2002_pdf/34_MacBeth.pdf
>> ::>
>> ::> i worry, tho, that with their sample size of 50 bikes they're
>> ::> not close to hitting the level of traffic we're expecting.  on the
>> ::> other hand, it's all about the sample rate ... not just the chip,
>> ::> tho, it's also limited by the properties of air in a tube.  but
>> ::> if the rate is high enough, it ought to be able to reduce this
>> ::> problem to an acceptably low level.
>> ::>
>> ::> > At 15mph, bikes wheels spaced 1.3cm apart will hit the sensor within
>> 2ms
>> ::> > of each other (hitting Paul's 500MHz example).  1.3cm ain't big, but
>> it
>> ::> > also ain't tiny.  I could see this happening in reality....so the
>> question
>> ::> > is, what do you do with the missing/bad counts/anomalies?  Is it ok
>> to
>> ::> > drop somebody?
>> ::>
>> ::> one option is to funnel the ride through some narrow counting
>> ::> point where the possibility of side-by-side riders is lower,
>> ::> and lay the tube there.  another is to use multiple counters
>> ::> in multiple locations and average the results.  (i was going
>> ::> to suggest running a group of tubes at different angles, until
>> ::> i imagined riding over that naked. =)
>> ::>
>> ::> -m-
>> ::> _______________________________________________
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>
>
> --
> -Frank Canaan
> fcanaan at gmail.com
>
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