What is on those TdF bikes?

[Mseries]

Peter wrote:
> MSeries wrote:
>
>> rosco" <reverse-the-following"ocsor_g wrote:
>>
>>
>>> They could supply RFID tags for all the team's bicycles
>>> including the backup ones. The new tag should still
>>> register when it crosses the finish line. After the
>>> fact, they must have some manual process to associate
>>> the new tag with a particular rider. It would be easier
>>> if the riders could just wear the tag like runners do.
>>
>>
>> The feedback loop on the road is 1.2m past the finish
>> line, the transponder it 1.2m behind the front of the
>> front wheel.
>
> ? I presume you mean the sensor on the road is 1.2 m
> before the finish line so that the transponder on the
> bike would be over it just when the front wheel reaches
> the line.
>
yes

 

[Mseries]

Tim McNamara wrote:
> "MSeries" <[email protected]> writes:
>
>> rosco" <reverse-the-following"ocsor_g wrote:
>>
>>>
>>> They could supply RFID tags for all the team's bicycles
>>> including the backup ones. The new tag should still
>>> register when it crosses the finish line. After the
>>> fact, they must have some manual process to associate
>>> the new tag with a particular rider. It would be easier
>>> if the riders could just wear the tag like runners do.
>>
>> The feedback loop on the road is 1.2m past the finish
>> line, the transponder it 1.2m behind the front of the
>> front wheel. Attaching the transponder to the rider would
>> be less accurate since the placings and timings are taken
>> on the bike not the rider
>
> Yes, but the leading edge of the front wheel, not some
> spot on the rear triangle.

The sensor is 1.2m before the finish line (not after like I
said yesterday) and the transponder is 1.2m behind the front
of the front wheel so when the transponder triggers the
senser, the front wheel is crossing the line.

 

[Blue Gator]

"Edward Dike, III" <edd(2+1)[email protected]> wrote in message
news:daTGc.8$%[email protected]...
>
> "Mark Hickey" <[email protected]> wrote in message
> news:[email protected]...
> | "Edward Dike, III" <edd(2+1)[email protected]>
> | wrote:
> |
> | >
> | >"LAN Support" <[email protected]> wrote in message news:40eb6ec6$0$41643$c30e37c6@lon-
> | >reader.news.telstra.net...
> | >| The tags aren't used for determining finishing order,
> | >| as their time resolution isn't good enough. They just
> | >| record which riders finished
in
> | >| which bunch. Photofinish camera are still used to
> | >| determine placings.
> |
> | >Chip timing resolution is .01 second for running/
> | >skating races;
probably
> | >greater if needed.
> |
> | At 40mph / 65 km/h .01 seconds is only good down to a
> | resolution of .18m (or a little over 6"). There can be
> | several bikes squeezed into that space. They'll be
> | keeping the cameras for a while it appears.
> |
> | Mark Hickey Habanero Cycles http://www.habcycles.com
> | Home of the $695 ti frame
>
> Given the unparalleled stakes of the TdF, and reliability
> issues with chip timing in general- occasional missed
> scans at starts/ finishes, that's a good thing.
>
> Whoa to the poor soul who trips on the extension cord and
> unplugs it at
the
> wrong moment.
>
> I suspect the resolution is mostly a function of the
> spreadsheets used to record data. I have no idea what it
> takes to overwhelm a chip timing system, but high speed
> film allows for the input of human judgments, and
> verification by almost anyone viewing the results, which
> certainly adds to the credibility of the results.
>
> ED3
>
>

IIRC, something was said on OLN during the prolog that while
times were being shown in hundredths of a second, they were
actually recorded out to eight decimals.

This is the same technology used to time Indy car races. If
they can accurately track cars that travel well over 200 mph
then they should be able to do the same with a bicycle.

Arlie C.

 

[Ryan Cousineau]

In article <xo_Gc.25272$JR4.792@attbi_s54>,
"Blue Gator" <[email protected]> wrote:

> IIRC, something was said on OLN during the prolog that
> while times were being shown in hundredths of a second,
> they were actually recorded out to eight decimals.

Don't believe the hype. If they're really getting data
with any accuracy to the nearest hundred-millionth of a
second, I'll eat my hat. The nice, pink Campagnolo cycling
cap I just got.

I would believe that they were getting moderately credible
data to the nearest thou or even ten-thou, but the rest is
probably down to statistical fuzz.

At 50 km/h, the cyclists are travelling at tetch over 45
feet/s, or just under 14 m/s. The quantities aren't
important except as general, plausible values.

so, in one one hundred-millionth of a second, a bicycle at
14 m/s travels 0.00000014 m. 1.4x10^-8 m. 14 nanometres.

I'm a pedant, so I went searching for things that big. I
found one on the web!

http://www.umass.edu/newsoffice/archive/2000/121400nano.html

They're building "nanowires" that thick, touted as 10,000
times thinner than a human hair. There is no way the
transponder is positioned with nanometre accuracy (I suspect
the organizers would be happy with millimeter accuracy), so
right there goes most of your decimal places, and that makes
the rash assumption that everything else in the system is
nanometre-accurate.

> This is the same technology used to time Indy car races.
> If they can accurately track cars that travel well over
> 200 mph then they should be able to do the same with a
> bicycle.

It's not that hard to track a fast-moving object. Compared
to radio waves, they're really slow . Thousandths of a
second are within reach of this technology. For measuring
nanoseconds, you need slightly higher technology.

I'm actually not very impressed with fretting over
greater accuracy than we have. I think it's okay to look
at really close results and just declare that no
meaningful performance difference has been measured, and
that it's a tie.

--
Ryan Cousineau, [email protected] http://www.wiredcola.com
President, Fabrizio Mazzoleni Fan Club

 

[David Reuteler]

MSeries <[email protected]> wrote:
> The sensor is 1.2m before the finish line (not after like
> I said yesterday) and the transponder is 1.2m behind the
> front of the front wheel so when the transponder triggers
> the senser, the front wheel is crossing the line.

nope, can't see the cheat there. anyway wouldn't you have to
place it within a nanometer?
--
david reuteler [email protected]