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'lap timing project'
1999\03\10@141435 by Mark

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Has anybody developed a DIY lap timing project (for cars)that they would
like to share?

I have been looking at alternative methods for the car to trigger completion
of a lap, the objectives being repeatability and operation from only one
side of the track (ie not a sensor on either side of the track).

I think, but am not absolutely sure, that the systems for sale (minimum of
300 UK pounds) operate by a trackside beacon transmitting an infra-red pulse
that is picked up by a receiver mounted in the car (or vice-versa?) which
displays the lap time, lap, etc.

I have been looking at using an infra-red remote control switch (from
Maplins), but this would need modifying to output a continuous pulse train.
This may be a bit OTT for this project.

Can I simply use (read very few components) an infra-red transmitter
emitting a pulse train, which is then received in the car by the receiver
triggering a lap which is then input into the PIC which does all the data
processing.

Can anybody suggest simple transmitter/ receiver circuits that will operate
over a minimum of 10 metres in all weather conditions.


Thanks
Mark

1999\03\10@145458 by Andy Kunz

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>I think, but am not absolutely sure, that the systems for sale (minimum of
>300 UK pounds) operate by a trackside beacon transmitting an infra-red pulse
>that is picked up by a receiver mounted in the car (or vice-versa?) which
>displays the lap time, lap, etc.

The ones used in the USA are based on very-short-range radio.  The antenna
is a line beneath the carpet.

Andy

  \-----------------/
   \     /---\     /
    \    |   |    /          Andy Kunz
     \   /---\   /           Montana Design
/---------+   +---------\     http://www.montanadesign.com
| /  |----|___|----|  \ |
\/___|      *      |___\/     Go fast, turn right,
                              and keep the wet side down!

1999\03\10@152959 by Andy

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>>I think, but am not absolutely sure, that the systems for sale (minimum of
>>300 UK pounds) operate by a trackside beacon transmitting an infra-red
pulse
>>that is picked up by a receiver mounted in the car (or vice-versa?) which
>>displays the lap time, lap, etc.
>
>The ones used in the USA are based on very-short-range radio.  The antenna
>is a line beneath the carpet.
>
>Andy


Does your wife not go mad about the tyre marks round the carpet?? some years
ago (many) my boss caught me racing round his ware house in my custom pickup
he went totaly nutts!! I thought the squeeling noise was ace but i was only
a teenager!
                 Andy. E.

1999\03\10@162518 by Andy Kunz

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>Does your wife not go mad about the tyre marks round the carpet?? some years
>ago (many) my boss caught me racing round his ware house in my custom pickup
>he went totaly nutts!! I thought the squeeling noise was ace but i was only
>a teenager!

I was thinking of model cars, not real ones.

I don't run the models.  My toys need wetness under them.

Andy

  \-----------------/
   \     /---\     /
    \    |   |    /          Andy Kunz
     \   /---\   /           Montana Design
/---------+   +---------\     http://www.montanadesign.com
| /  |----|___|----|  \ |
\/___|      *      |___\/     Go fast, turn right,
                              and keep the wet side down!

1999\03\10@165008 by Andy

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>>Does your wife not go mad about the tyre marks round the carpet?? some
years
>>ago (many) my boss caught me racing round his ware house in my custom
pickup
>>he went totaly nutts!! I thought the squeeling noise was ace but i was
only
>>a teenager!
>
>I was thinking of model cars, not real ones.
>
>I don't run the models.  My toys need wetness under them.
>
>Andy


Sorry, I just saw the chance to add some humor, I had guessed that you were
on about models, was the other guy?? I have a friend who used to race real
ones and he was also in to the telemetry side of things, he's also an
electronics engineer (one of the best), I could get some ideas off him if
its for a real race car, as for my kicks they certainly don't include water
as I'm scared stiff of it!, did used to fly a fair bit though!
          Cheers,
                       Andy. E.

1999\03\10@171915 by Mark

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Andy,
We are talking real cars here (small ones, anyway:
http://members.aol.com/fiatracing/main.html
although a system for model cars may have some read across to the real
thing.  Any info would be useful, particularly confirmation of how existing
commercial systems work.

Thanks
Mark


> {Original Message removed}

1999\03\10@181328 by Andy

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I would suggest a mate with a stop watch and a headset or chalk board, have
you tried to use a read out while hammering along with loads of people
chasing your tail (or in front of you if your unlucky!), you can usually get
loads of free help as people love to boast, you could give them a title and
they'd love it!.
alternatively infra red would be a good ides as there are probably a lot of
rf devices at the track side any how, you could modulate it with a tone to
avoid false triggering, shield the sensor in the car with a tube and filter
for the modulated signal as you passed to trigger a simple count, there are
a few designs around for driving a display from the pic, for the software
you'd have to ask around as that's not my field (yet)
Don't Know what country your in but you could get timing from the atomic
clock signal providing it gives the right sort of signal, you can turn this
into an 8 bit (I think its 8) output!
I will ask my mate tomorrow how they realy do it but I don't think they
bothered, they just went like hell and hoped, didn't do to well judging by
the tyre marks up his crash helmet and the lack of wheels on the returned
car (formula ford)
Cheers,
          Andy. E.

{Quote hidden}

>> {Original Message removed}

1999\03\11@071901 by Mark

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Andy,
Stop watch and pitboard are the current method, but most people are
switching over to a 'Hot Lap' system which displays lap times and lap number
in the car.  Considering how I think they work the cost of at least 300 UK
pounds is excessive, hence the DIY version.
I have managed to find a couple of circuits, but the range is limited.   Any
ideas what defines the range, is it the performance of the IR components or
the circuits driving them?

Mark

> {Original Message removed}

1999\03\11@081057 by chris hornby

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>
I have managed to find a couple of circuits, but the range is limited.   Any
ideas what defines the range, is it the performance of the IR components or
the circuits driving them?
<

Is their not a danger of it screwing up if the IR is blocked by another car pass
ing between you and the pitwall. are their any other options beside IR?.

CH.

1999\03\11@084653 by Andy

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>>
>I have managed to find a couple of circuits, but the range is limited.
Any
>ideas what defines the range, is it the performance of the IR components or
>the circuits driving them?
><
>
>Is their not a danger of it screwing up if the IR is blocked by another car
passing between you and the pitwall. are their any other options beside IR?.
>
>CH.


Funny you should mention that as I was thinking that at about 3 this
mornin', could timing be taken by detecting the white start line with a
sensor under the car? is there not any standard signal provided by track
owners? . You could still use the pit board method but send the information
to the car. Do you realy need to know your lap time as I cant see
(understand) how it helps?.
Let me know if theres a white start line, as for infra red you could use a
verticle tube with an inverted conical reflector at the top with sensor at
the point and the trackside emiter in the bottom of a tube pointing at the
track.
Laters,
          Andy.

1999\03\11@094509 by Mark

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Andy,
White start line is a very good idea, but the starting grid also uses white
lines which could result in false triggering.  I suppose this system is
similar in principle to a previous suggestion with a reflective strip on the
pit wall.
Unfortunately track owners do not provide a standard signal, but one of the
major timing system manufacturers has recently installed a timing beacon at
all the major circuits....I wonder if I could tap into this beacon signal, a
bit more research is required.
The lap time is useful, particularly in qualifying, as an indication of
improvement and comparison with known good lap times.  Also, the system I am
planning to build will record the first lap time, calculate the average
speed, then display a +/- bar to indicate whether the car is on target to
improve its previous lap time.

Mark

{Quote hidden}

1999\03\11@094925 by Adam Bryant

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Don't the Formula 1/Indy circuits use some kind of RF ID tag for lap
tracking and timing? With a sensor placed next to the start/finish line
all you would need in the car is a small RF ID tag.  This would have the
benefit of not getting dirty and could be easily expandable to add on
additional cars.

Adam Bryant (age 0x23)
spam_OUTabryantTakeThisOuTspampeaktech.com (work)
.....adamdbKILLspamspam@spam@juno.com (home)
Parker, CO, USA
Robotics, RC Airplanes, anything using a PIC

On Thu, 11 Mar 1999 13:46:58 -0000 Andy <andyspamKILLspamNET3.FREESERVE.CO.UK>
writes:
{Quote hidden}

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1999\03\11@101251 by chris hornby

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You could stick to the IR idea and have the transmitter at a hieght of 6-8 feet
so that it looks down at the vehicle, nothing should be able to break its line
of sight then, unless its caravan racing.

CH.

1999\03\11@104932 by Mark

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Chris,
good point, but having now done some more research IR seems to be the system
that everybody uses.  I suppose the probability of the signal being
completely blocked is fairly minimal, so a missed lap is considered
acceptable.
I did consider using a radio transmitter/receiver system but I don't believe
the signal can be focussed down to the point where the car crosses the line,
or can it??

Mark


> {Original Message removed}

1999\03\11@110558 by Mark

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Adam,
sounds good to me (I think this is how the systems at my local kart tracks
work) but how do they focus the signal to a very narrow band, ie the start
finish line?

Mark

> {Original Message removed}

1999\03\11@114948 by Adam Bryant

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I have no idea how they would focus the signal that closely (not being an
EE by trade).  I know that at least one of the major tracks here in the
U.S. (Indianapolis?) is using a system like this.  IIRC they can track
every car on the track and get very precise lap times from it.  This was
probably also a very expensive system.  For a low cost system you may get
fairly consistent results based on the fact that the RF ID tags have a
very limited range.  The RF ID tag should trigger at about the same point
on the track every lap, even if this point is a few feet +- from the
actual finish line.

Adam Bryant (age 0x23)
.....abryantKILLspamspam.....peaktech.com (work)
EraseMEadamdbspam_OUTspamTakeThisOuTjuno.com (home)
Parker, CO, USA
Robotics, RC Airplanes, anything using a PIC

On Thu, 11 Mar 1999 16:06:19 -0000 Mark <markspamspam_OUTSCOOBYWRX.FREESERVE.CO.UK>
writes:
>Adam,
>sounds good to me (I think this is how the systems at my local kart
>tracks
>work) but how do they focus the signal to a very narrow band, ie the
>start
>finish line?
>
>Mark
>
>> {Original Message removed}

1999\03\11@120204 by Andy Kunz

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At 10:20 PM 3/10/99 -0000, you wrote:
>Andy,
>We are talking real cars here (small ones, anyway:
>http://members.aol.com/fiatracing/main.html
>although a system for model cars may have some read across to the real
>thing.  Any info would be useful, particularly confirmation of how existing
>commercial systems work.

Visit http://www.airage.com and ask the people there (@spam@gerryyKILLspamspamairage.com
would be a good start).  They did a review of a lap system not too long
ago.  I did an IR laser system myself some time ago.

Andy


  \-----------------/
   \     /---\     /
    \    |   |    /          Andy Kunz
     \   /---\   /           Montana Design
/---------+   +---------\     http://www.montanadesign.com
| /  |----|___|----|  \ |
\/___|      *      |___\/     Go fast, turn right,
                              and keep the wet side down!

1999\03\11@123303 by Keith M. Wheeler

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At 01:46 PM 3/11/99 -0000, Andy wrote:
>
>Funny you should mention that as I was thinking that at about 3 this
>mornin', could timing be taken by detecting the white start line with a
>sensor under the car? is there not any standard signal provided by track
>owners? . You could still use the pit board method but send the information
>to the car. Do you realy need to know your lap time as I cant see
>(understand) how it helps?.
>Let me know if theres a white start line, as for infra red you could use a
>verticle tube with an inverted conical reflector at the top with sensor at
>the point and the trackside emiter in the bottom of a tube pointing at the
>track.
>Laters,
>           Andy.

I've had a couple of off-list comments exchanged with Mark.  We built
a lap timer for use in the boss's roundy-round (circle track) stock
car.  We use some industrial sensor the boss picked up (expensive $100+)
to detect a reflective strip on one of the catch-fence posts.  It works
suprisingly well, and only rarely do we miss a lap. Of course road courses
bring in a higher level of logistical concerns.

The problem with detecting a painted line on the track surface:  there
are usually other lines, the curbing is bright and reflective (and you
use the curbing, depending on car/class skill and need), and some road
courses are temporary--closed roads or runways.

As far as helping:  my boss and his team (4 cars?  I forget, I
dont' drive in circles I do sports cars) do like the lap timers.
Lap time is *the* measuring criteria for performance.  Ours has a
"recall" function.  You can toggle through the recorded lap times.
Of course this is incredibly helpful in test and tuning, but the
drivers also use it when in yellow flag condition.  A minor change
of line or braking point can have a tremendous effect on lap time,
and if done right, the fastest lap feels the slowest.  Of course,
in the case of these circle track cars, we are dealing with classes
that don't allow radio communications, and a track with no place for
folks with pit boards.

Um, PIC?  Yes, it's got a slot for a 40 pin device, 16C65/16C74.  Actually
the processor board is just a development/break-out type board, with
the display and switch board custom to the lap timer.

The coolest thing about this gizmo (and lets face it, "cool" is an
important part of making and marketing things) is that the LEDs are
easily visible from the stands, and when it's powered up, it reads
"Ford"--my boss's team has the only fords out there.

-Keith Wheeler
ARMA Design                             http://www.ARMAnet.com/

1999\03\11@123310 by Wagner Lipnharski

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Mark wrote:
>
> Adam,
> sounds good to me (I think this is how the systems at my local kart tracks
> work) but how do they focus the signal to a very narrow band, ie the start
> finish line?

Mark, as I said before, "a burried deflector and antenna".
Imagine a grounded "U" shape metal, long enough to cross entirelly the
race track, burried, with the opening on the up side, with an antenna
inside. It will only irradiate or receive irradiation from the angle
that the U shape allows it.  There are several metal frames in that
shape that can be used, at any size you want.  Something similar to
that (the idea) is used to beacon aiplane radio navigation. It is
quite precise and you can get RF cones of just 1¡ if you want.

Note that telemetry is something that, as you said "one lap missed
is unacepptable", so, this antenna has the job to "inform" the computer
inside the car about when it crossed a point, and that computer will
transmit that information over other radio frequency carrier to the
pitstop or the control center.  You can also install a special
transmitter on each car, and that antenna will collect the crossing
of those cars, circuits will detect special frequencies and identify
which car crossed... but to go to a millisecond precision, you
can't do that. Remember, at 300km/h it means 8.3cm per millisecond.
So, your detection system needs to identify the car in a strip of
only 8.3cm (3¹") to be able to get it inside the millisecond.
Sometimes this is not enough to transmit a special tone or code,
then this is why the post transmission is a good idea.

Other idea is using a stripe pained on the asphalt, using a special
reflective ink, use some sensors on the bottom of the car. This
can be painted at some point of the track where no tire marks
would interfere the reading.

--------------------------------------------------------
Wagner Lipnharski - UST Research Inc. - Orlando, Florida
Forum and microcontroller web site:   http:/http://www.ustr.net
Microcontrollers Survey:  http://www.ustr.net/tellme.htm

1999\03\11@125103 by mlsirton

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Hi,

On 11 Mar 99 at 9:08, Keith M. Wheeler wrote:
<snip>
> At 01:46 PM 3/11/99 -0000, Andy wrote:
> >Funny you should mention that as I was thinking that at about 3 this
> >mornin', could timing be taken by detecting the white start line with a
> >sensor under the car? is there not any standard signal provided by track
<snip>
> The problem with detecting a painted line on the track surface:  there
> are usually other lines, the curbing is bright and reflective (and you
> use the curbing, depending on car/class skill and need), and some road
> courses are temporary--closed roads or runways.
<snip>

A thought...  To detect a certain point on the track you could create
a pattern (think of barcode) of several lines and detect that
pattern.  That would solve the problem with other lines on the track.
An error correcting code scheme could be applied to correct for oil
spills and erased lines... :-)

Hope this helps,
Guy - KILLspammlsirtonKILLspamspaminter.net.il

p.s. You could use paint that contained metal, magnetize it and read
it like a floppy disk with the car being the reading head... :-)

1999\03\11@134901 by jamesp

picon face
It can if you use a beam antenna.  The more elements the antenna
has, the narrower the beam.  If you use a UHF frequency, you can
have an antenna with many elements that is very directional, and
yet take up very little room.  Look at an Amateur Radio Handbook
for more details.  If you can't find one, let me know.  I'm an
Amateur Radio Operator and I'll help you if I can.

                                      Regards,

                                        Jim





{Quote hidden}

>> {Original Message removed}

1999\03\11@141831 by Wagner Lipnharski

picon face
There is UV reflective ink, paint a strip on the track, use a couple of
TX/RX UV diodes, nothing else will
reflect UV light like that strip. Easy, and low cost. You can build two
or three sets of those TX/RX leds,
left side, middle and right side of the car, in case one can't read it
because oil spills and rubber marks,
the other two will catch it.

If you paint several "coded strip" (one, two or three lines, as a code),
your electronics can identify which one the car is crossing, you can
develop not just a "lap time", but intermediate points of the track
speed and time, what could be "gracious" to the driver knows exactly
where he is good or not.  With some expertize about tire rotation versus
several laps done, you can develop a relation between both and describe
a whole interpolation along the race track based on the tire (or gear
box) rotation and speed. Of course sometimes it turns more or less than
the average but it can give you an aproximate curve, along with the real
numbers collected by the TX/RX UV sensors.

I would go for Radio in a more sophisticated version, or just UV
reflective for a cheap one.
--------------------------------------------------------
Wagner Lipnharski - UST Research Inc. - Orlando, Florida
Forum and microcontroller web site:   http:/http://www.ustr.net
Microcontrollers Survey:  http://www.ustr.net/tellme.htm

1999\03\11@151459 by Mark

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Wagner,
I like this idea, with some mods.....
Markings on the track, radio antennas in the track, sensors on either the
track, etc are all no go; any sensing must be remote from one side of the
track only.
Taking your idea, do you think it would be possible to paint a stick/board
with the ink, which is then mounted trackside and mount the array of TX/RX
leds in the car?
Scanning range is a significant issue, can the sensors work over a range of
10m+ (approx 30ft+)?
Where can I get this ink from?

Thanks
Mark

> {Original Message removed}

1999\03\11@165846 by Andy Kunz

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>Taking your idea, do you think it would be possible to paint a stick/board
>with the ink, which is then mounted trackside and mount the array of TX/RX
>leds in the car?
>Scanning range is a significant issue, can the sensors work over a range of
>10m+ (approx 30ft+)?
>Where can I get this ink from?

Why don't you just paint the car as a giant barcode and put up a
super-market scanner in the pit wall <G>.

Andy


  \-----------------/
   \     /---\     /
    \    |   |    /          Andy Kunz
     \   /---\   /           Montana Design
/---------+   +---------\     http://www.montanadesign.com
| /  |----|___|----|  \ |
\/___|      *      |___\/     Go fast, turn right,
                              and keep the wet side down!

1999\03\11@193321 by Mark

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picon face
Andy,
that would be really neat for a new graphics scheme for the car, the butt of
many a joke i'm sure!
Seriously though, a supermarket scanner.........

Mark

> {Original Message removed}

1999\03\11@210821 by Wagner Lipnharski

picon face
UV sensors need to work very close, well, at least for the ones
available  at the market, except if you use a UV laser and a
regular UV phototransistor (PIN?) with focused lenses.
By this way you can build also a speed radar....

But I don't understand why it needs to be at side of the track...
why not paint a strip on the track asphalt?
Even with all the rough environment, and tires just scrapping the ink,
what will stay on the little depressions of the asphalt or concrete
will still reflecting UV for long time.  The car will be inches from
the asphalt, so it will be very easy to use.

Other point, under the car, the asphalt will be always in the shade,
no sun or any other lights reflecting to the pin diode...

At side of the track you can not ensure that the car will not be
blocked by another car... this is the first reason not to install
it horizontally.  It is quite impossible to another car to be under
your car... well, only if you are not a good driver... hehe.

3M has some high reflective inks for safety and other uses.
Scotchlite=99 Reflective Ink, 3M=99
or take a look at this:
3M=99 Scotchcal=99 U.V. Screen Printing Inks Series 9700
at this url: http://www.mmm.com/tcm/pc/gvm/chartLEV.html

have fun, and tell me if it worked nice, I want a percentage of
your profit. :)

--------------------------------------------------------
Wagner Lipnharski - UST Research Inc. - Orlando, Florida
Forum and microcontroller web site:   http:/http://www.ustr.net
Microcontrollers Survey:  http://www.ustr.net/tellme.htm

1999\03\11@211232 by Wagner Lipnharski

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Mark wrote:
> that would be really neat for a new graphics scheme for the car, the butt of
> many a joke i'm sure!
> Seriously though, a supermarket scanner.........
>
> Mark

Yeah, right, make the track pass right aside of the
supermarket cashier girl, she can scan it along with
the other products;
"Tomatoes $1.37", "Italian Bread $1.12",
"Grade A Milk Gallon $1.37", "Car#32 238mph",
"Jelly Beans $0.68"...
--------------------------------------------------------
Wagner Lipnharski - UST Research Inc. - Orlando, Florida
Forum and microcontroller web site:   http:/http://www.ustr.net
Microcontrollers Survey:  http://www.ustr.net/tellme.htm

1999\03\11@234157 by Vincent Deno

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This may be way off (because i have never done any research on this topic)
but what about using a laser?  The diodes have become quite cheap,
especially for low power apps like this would require.  Don't ask about
the receiver because I don't know the specifics.  Porbably could use an
current to voltage amp hooked to an idential diode for receiving.  Just a
thought.

--------------
Vincent Deno
Design Engineer
Theta Digital Corp.
http://www.thetadigital.com
RemoveMEdenovjTakeThisOuTspamemail.uc.edu
_____________
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|/| | | | | |\|
| | |/| |\| | |
| | | | | | | |
| |_/ | | \_| |
| |   | |   | |
|_/  /___\  \_|

1999\03\12@012026 by Quentin

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I've been following this thread, just out of interest.
What about using RFID?
To expensive? (scanner, etc.)
Range?
I've never used them, just a thought.

Quentin

1999\03\12@012226 by Jim Paul

picon face
The problem here is dangerous laser radiation.  If it accidently entered the
eye(s) of a driver,
(s)he could be blinded momentarily or even permanently.  I don't believe you
would want that
to happen.  Lasers would not be my first choice unless you could idiot proof
it somehow so
that it could never cause injury.  Of course, you may have this all worked
out already.


Regards,


Jim
{Original Message removed}

1999\03\12@020456 by Wagner Lipnharski

picon face
Jim Paul wrote:
>
> The problem here is dangerous laser radiation.  If it accidently entered the
> eye(s) of a driver,
> (s)he could be blinded momentarily or even permanently.  I don't believe you
> would want that
> to happen.  Lasers would not be my first choice unless you could idiot proof
> it somehow so
> that it could never cause injury.  Of course, you may have this all worked
> out already.
>
> Regards,
>
> Jim
> {Original Message removed}

1999\03\12@111459 by Andy Kunz

flavicon
face
At 12:34 AM 3/12/99 -0000, you wrote:
>Andy,
>that would be really neat for a new graphics scheme for the car, the butt of
>many a joke i'm sure!
>Seriously though, a supermarket scanner.........

How about a 10W laser one then.
  \-----------------/
   \     /---\     /
    \    |   |    /          Andy Kunz
     \   /---\   /           Montana Design
/---------+   +---------\     http://www.montanadesign.com
| /  |----|___|----|  \ |
\/___|      *      |___\/     Go fast, turn right,
                              and keep the wet side down!

1999\03\12@130116 by Lester Wilson

flavicon
face
Hi,

re lap timing project.

How about using  contactless Smart Cards. The cards will transmit their ID
plus other data as they pass through the field of the Reader Writer.

The vehicle needs to be within 2Mts of the antenna, so a simple wire antenna
over the track should suffice.

The Reader Writer handles all encryption etc and passes decoded data out in
RS485.

The "cards" can be attached to the vehicle via tape on the inside of the
screen or even on the roof. The are pretty robust.

Lester

1999\03\12@135743 by Wagner Lipnharski

picon face
Lester Wilson wrote:
>
> Hi,
>
> re lap timing project.
>
> How about using  contactless Smart Cards. The cards will transmit their ID
> plus other data as they pass through the field of the Reader Writer.
>
> The vehicle needs to be within 2Mts of the antenna, so a simple wire antenna
> over the track should suffice.
>
> The Reader Writer handles all encryption etc and passes decoded data out in
> RS485.
>
> The "cards" can be attached to the vehicle via tape on the inside of the
> screen or even on the roof. The are pretty robust.
>
> Lester

Just need to see if at the car speed of 230mph, what
correpond to 8cm/ms, or 25ms during the 2m window time
it will be able to the transponder receive the magnetic
power field, charge the transmitter and transmit the
code, all of this in 25ms?  Here in Orlando we use the
EPASS, I have it in two cars, it automatically pays the
road tolls, it works pretty nice even speeding at 45mph,
they recommend not to go after 25mph near to the sensors,
but at 230mph?  and the sensor can read just one unit at
time, what about several cars crossing the "antenna" at
the same time?  Other point is that no car_race_track
owner will allow to install a wire crossing the track
just one meter above the cars...
--------------------------------------------------------
Wagner Lipnharski - UST Research Inc. - Orlando, Florida
Forum and microcontroller web site:   http:/http://www.ustr.net
Microcontrollers Survey:  http://www.ustr.net/tellme.htm

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