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

[Donald Delmar Davis]

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-
> _______________________________________________
> dorkbotpdx-blabber mailing list
> dorkbotpdx-blabber at dorkbot.org
> http://music.columbia.edu/mailman/listinfo/dorkbotpdx-blabber

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://music.columbia.edu/pipermail/dorkbotpdx-blabber/attachments/20080528/148b2a17/attachment.html