How to: Record Lap Times

[beeza]

I'm after a device I can have in my car when doing laps and have real time display of the lap just finished.

I read somewhere recently where somebody said someone had a mobile phone in thier car that via satelite was able to achieve this.It would be good to avoid using a mobile because of costs but if that's the only way,sweet.

Thank U.

[CRXer]

go to racechrono.com & see if u have a compatible mobile or can get one cheap.then just get a bt gps receiver(about $50-100),download software for free from racechrono & u have free lap timing all day long,fairly accurate as well.

[beeza]

Thank U!!!!

Taken from the website:

"Q: How accurate are the lap times?
A: Accuracy of the lap times is fully dependent on quality of your GPS signal. If GPS signal is weak, RaceChrono can be inaccurate and will probably even miss your traps (will not record a lap time). GPS signal quality is affected by your GPS receiver quality and its placement. Recommended place in a car is as close to your windshield as possible. On some cars and some receivers, you will not get proper GPS signal when installed inside the car. As well as GPS signal quality, the placement of the finish and start lines affects the timing accuracy. Trap lines should not be set to tight corners, or to places where you usually do braking. Lap timing with a normal 1 Hz GPS and RaceChrono achieves +-0.25 seconds accuracy or better, and with 5 Hz GPS the accuracy will be better than +-0.15 seconds."


So better to get a good gps reciever.Would a 1Hz gps reciever be enough or is there anything I should be looking for in a gps reciever?
Where can I buy one? (Dick smith's?)

Thank U,excellent!

[beeza]

"Using the internal GPS
RaceChrono supports the internal GPS on some phone models, but unfortunately the accuracy of RaceChrono suffers quite a bit when used with the current internal receivers.

The lap timing accuracy with an internal GPS can sometimes be relatively good, but a good external Bluetooth GPS is recommended for frequent track day use. One of the best receivers currently is the QSTARZ BT-Q818 eXtreme!"

[CRXer]

Thank U!!!!

Taken from the website:

"Q: How accurate are the lap times?
A: Accuracy of the lap times is fully dependent on quality of your GPS signal. If GPS signal is weak, RaceChrono can be inaccurate and will probably even miss your traps (will not record a lap time). GPS signal quality is affected by your GPS receiver quality and its placement. Recommended place in a car is as close to your windshield as possible. On some cars and some receivers, you will not get proper GPS signal when installed inside the car. As well as GPS signal quality, the placement of the finish and start lines affects the timing accuracy. Trap lines should not be set to tight corners, or to places where you usually do braking. Lap timing with a normal 1 Hz GPS and RaceChrono achieves +-0.25 seconds accuracy or better, and with 5 Hz GPS the accuracy will be better than +-0.15 seconds."


So better to get a good gps reciever.Would a 1Hz gps reciever be enough or is there anything I should be looking for in a gps reciever?
Where can I buy one? (Dick smith's?)

Thank U,excellent!

i got a 5Hz receiver off egay for bout $60 delivered,so have a look on there.

1Hz will be accurate enough as i found my receiver within like an average .02secs of the official track timing device,& others with 1Hz seemed to be ok.

one thing i did notice though is when trying to overlay the laps of others with 1Hz & i had 5 Hz on the PC, was they didnt overlay well,so hard to compare what lines people were taking thru corners, so basically if u & some mates are gonna setup this way & want to compare laps,i would prob all go for the same brand of gps receiver so things will compare better & getting the highest refresh rate u can afford will prob help this as well,but if just for yourslef than 1Hz will prob keep u happy.

[CRXer]

"Using the internal GPS
RaceChrono supports the internal GPS on some phone models, but unfortunately the accuracy of RaceChrono suffers quite a bit when used with the current internal receivers.

The lap timing accuracy with an internal GPS can sometimes be relatively good, but a good external Bluetooth GPS is recommended for frequent track day use. One of the best receivers currently is the QSTARZ BT-Q818 eXtreme!"

internal gps is crap still on most phones,much cheaper & better to source external gps still.

[aaronng]

I've got an ebay Globalsat BT338 satnav and running it on my work's 6120 classic.

[CRXer]

heres one like mine still only $10 with few hours to go,have a punt.

eGaaaaaaaaaaaaaay (http://cgi.ebay.com.au/G66-slim-66-Ch-Bluetooth-GPS-Receiver-NAV-SAT-New-UK_W0QQitemZ270379912925QQcmdZViewItemQQptZUK_CE_G PS_Accessories_Software_ET?hash=item270379912925&_trksid=p3286.m63.l1177)

[beeza]

Thanks again CRX'er! That's great mate,I'm going to the track on the 9th so I might just go to dick smith's,actually J car is better and ask for a 1Hz gps reciever.

It's all very easy! :)

[beeza]

heres one like mine still only $10 with few hours to go,have a punt.

eGaaaaaaaaaaaaaay (http://cgi.ebay.com.au/G66-slim-66-Ch-Bluetooth-GPS-Receiver-NAV-SAT-New-UK_W0QQitemZ270379912925QQcmdZViewItemQQptZUK_CE_G PS_Accessories_Software_ET?hash=item270379912925&_trksid=p3286.m63.l1177)

Wow,that's cheap!

So it's obviously ok?

I will go for this one and hold off,no rush :D

[beeza]

In the feedback they all say it's a great ite,so I'm a gonna bid for that,thanks heaps CRX'er!!!!

[CRXer]

mine works fine,only had it for like 12 months so cant tell u the longevity of the product,but battery & function is still going good atm.

but at this sort of price,worth a punt in any case,like i said i paid $60 delivered,so dont go much past a $50 bid on it.

[beeza]

Yeah yeah,I hate bidding,it finishes at 5.30am,I won't be up to compete.There are other's but bidding sux's,never win.

[beeza]

I didn't even ask but does it cost to use it,I'm on pre-paid?

[CRXer]

its gps,its free just like any other gps device. your thinking of those web based navigation options.

[beeza]

Oh excellent! I just didn't know cause I'm not a computer tech head.

What a cheap,great and simple to use system!

So if you want to stop incoming calls while racing,would U just do that in your phone settings? (not that I'm that popular or anything lol)

[beeza]

Here's (http://www.jaycar.com.au/productView.asp?ID=XC4895&keywords=xc4895&form=KEYWORD) the one (only one) Jaycar are selling for $99.

http://i99.photobucket.com/albums/l287/beeza2/productLarge_10453.jpg

It looks great to me,what to U think CRX'er? :)

[CRXer]

sorry dont know anything about that one,whats the specs on it?

it all depends what u want,ebay-cheaper,have to wait,more hassle with warranty or jaycar-more expensive,dont have to wait,good warranty.

if u dont want incoming calls,just switch phone to offline if yours has that.

[CRXer]

sorrry missed your little linky thing,specs on that are fairly average its a 1Hz refresh,accuracy is average.Also it says $149 when i opened the link?

if thats the case,id def try to snag one of the ebay ones instead,u'll prob pick up ones similar to those specs for less than $40 or maybe even a 1c wonder if u get lucky.

[beeza]

I rang them up and he said $99 but it says on the site that 1Hz - 0.25 sec accuracy and 5Hz - 0.15 sec.Is that the difference with the Hz rating or will the refresh rate being at 1Hz be an issue at all do you think?

It is a little bigger but where do U mount your's?

[beeza]

http://www.evoluscence.fr/kart/lap.jpg

This is some time comparisons with the 1Hz and official time.Looks fine for the track,the 1/4 mile would need to be more accurate,it seams there would be more trust in the 5Hz unit for that.

How accurate are the track line displays with the 5Hz?

Thank U,lots of questions...

[CRXer]

i just stick the gps to the top of the dash ,with a bit of velcro & mount the phone behind the steering wheel where u can get a quick look at it after a lap(although bloody hard at wakey,cos as soon as u finish reading the time u find yourself halfway thru the kink)

u can see by those 1Hz time comparisons that it will be more than sufficient for u to see what happened at the end of any given lap,heres a comparison of my 5Hz,
track ----- gps
1.15.856 - 1.15.81
1.15.360 - 1.15.46
1.17.313 - 1.17.32
1.14.895 - 1.14.91
1.20.714 - 1.20.71
1.14.918 - 1.14.84

so as u can see its a little more accurate,but not enough to really bother u.
my main point is,if u want to overlay results with mates,etc,it is prob better if u & the people u are trying to compare with all have 5Hz models(maybe even of the same brand gps).
i tried overlaying mine with someone elses 1Hz data & the track shapes looked fairly different.ie u couldnt really compare the lines taken thru corners,braking points,etc. not that its ever going to be that accurate with this limited technology,but u can get some sort of an idea to compare with.
The 5Hz track shape also compared closer to the actual track shape.The lines are fairly good as well,i fishtailed a few times back & forth before i finally caught it at one stage & it shows up perfectly on one of the laps.

heres the fishtail,it started about where the mouse pointer is & cost me like 5secs:(

http://i58.photobucket.com/albums/g268/CRXer/ScreenHunter_02Apr300047.jpg



heres how the 1Hz & 5Hz overlay

http://i58.photobucket.com/albums/g268/CRXer/ScreenHunter_03Apr300050.jpg

[95civic]

If you're serious about recording lap times for a reasonable price (more than mentioned above) look at products such as the Alfano (pro) and Micron (4). They are used in many forms of motorsport and can record much more than just the lap times. Well worth it if you're looking for that little bit more!!

[beeza]

Thanks 95civic,I'll check it out!

U are legend CRX'er,thanks heaps!

I think for me finding the best lines to take would be easiest if I just get out there and do some laps and try different approaches while watching the lap times.
I just can't see the track line read out as having real feedback.It's just not real accurate like you said but just a lap time read out and knowing how I attacked that lap will be more than enough to work out the quickest way around the track.

So taking that all into consideration,I'm really just after lap times and I will follow this technology offcoarse and watch it improve.The wish list in the forum section looks good!

Have U tried your 5Hz at the 1/4 mile?

[jrco83]

so... if i have a gps in my car (tomtom or whatever) and an N80 that has the racechrono application, do i still need to get that bluetooth gps receiver you guys are talking about? or would my tomtom do the job?