South West Bikers | Motorcycle Forum

Can't use race chrono on iPhone so downloaded harrry's lap timer from App Store £5.99. Works well easy to use and most tracks are already installed.

Wont be that accurate though, the built-in GPS will only update a maximum of once a second and not the most powerful GPS, so may not even be once a second if it misses.

You're better off purchasing a cheap Android phone (I bought an old HTC phone, any Android phone made since about 2011 will be perfectly fine) and a 5Hz GPS, that updates 5 times a second. You can also get 10Hz and higher now too. Also Racechrono is free on Android.

The built in GPS will be better than nothing or counting in your head (I'm the current lap record holder at Cadwell with a 57second lap) but I'd rather hurt a cheap phone than an expensive primary phone if you do have a crash.

I have Racechrono on an android phone, at Mallory the trace was fine from the hairpin to Gerrards, then missed everything else until it got back to the hairpin, just drew a straight line.
and even though I had a 10hz gps unit bluetoothed to it, it used its internal gps.

I got the hatch phone the 10 hz gps Bluetooth thing downloaded all the tracks and off I went! Tried it at three different tracks and it was absolute rubbish for me! It wasn't Mapping, couldn't figure out where it was half the time and my lap times were in the minutes of maybe 10 times what they should be LOL basically this is what you get for free so I opted to change it for something a little bit more upmarket shall we say
I may get this app for my iPhone know that it just to see how they compare

ninjajockey wrote:I have Racechrono on an android phone, at Mallory the trace was fine from the hairpin to Gerrards, then missed everything else until it got back to the hairpin, just drew a straight line.
and even though I had a 10hz gps unit bluetoothed to it, it used its internal gps.

That would either be because the settings were wrong in Racechrono. In settings under Device #1 it should be the Bluetooth GPS receiver, not anything like 'Internal GPS receiver'

Also it could be down to a really thick cloudy day, no GPS will pickup perfect signal in thick cloud. You can try moving the GPS receiver to somewhere external so it has full line of sight with the sky. If it was thick enough for an external GPS receiver to struggle you can be sure any internal GPS receiver would never get a good signal either.

I find I get pretty good results with one of these ......



A significant improvement on my previous one ....

DynaMight wrote:Wont be that accurate though, the built-in GPS will only update a maximum of once a second and not the most powerful GPS, so may not even be once a second if it misses.

You're better off purchasing a cheap Android phone (I bought an old HTC phone, any Android phone made since about 2011 will be perfectly fine) and a 5Hz GPS, that updates 5 times a second. You can also get 10Hz and higher now too. Also Racechrono is free on Android.

The built in GPS will be better than nothing or counting in your head (I'm the current lap record holder at Cadwell with a 57second lap) but I'd rather hurt a cheap phone than an expensive primary phone if you do have a crash.

It's only for me to see if I improve over the day,so being dead accurate isn't an issue as it will be constant ,and it worked every session which race chrono never did.

DynaMight wrote:
The built in GPS will be better than nothing or counting in your head (I'm the current lap record holder at Cadwell with a 57second lap) but I'd rather hurt a cheap phone than an expensive primary phone if you do have a crash.

I did the head counting thing at Cadwell Last year, I only got to 22, does that mean I now am the record holder ?

gazaR1 wrote:

DynaMight wrote:

It's only for me to see if I improve over the day,so being dead accurate isn't an issue as it will be constant ,and it worked every session which race chrono never did.

Once you'd worked out how to turn it on

Hi bikers,

Just to clarify on internal GPS / accuracy and how to run a GPS based lap timer stable:

Update rate is not really relevant for timing accuracy. Harry's LapTimer e.g. interpolates the time the start / finish line is crossed. It takes the fixes before and behind the line and uses the speed development in addition to get precise numbers. As the start / finish line is typically placed on a straight and is passed at high speeds, accuracy for a 1 Hz and a 20 Hz will be nearly the same. Timing accuracy is a lot more influenced by GPS accuracy in terms of position accuracy. So to get time accuracy below 0.05 seconds it is more important to run the GPS in its comfort zone update wise but with high accuracy. As an example, the Qstarz818XT will deliver better timing accuracy at 5 Hz (DGPS) compared to 10 Hz.

External GPSes typically come at higher accuracy *and* higher update rates, so using one is certainly good. Especially when going into data analysis, higher update rates are necessary.

Harry's LapTimer offers 5, 10 and 20 Hz external GPSes for both the iOS and Android versions.

For bikers in particular: don't put the smartphone into your cloth. This degrades GPS accuracy and you may hurt yourself when crashing. Putting the device into a pocket (without an external GPS), is the most frequent reason for issues with GPS based timing - which is the reason I raise this item here.

Hope that helps,

- Harry

I think that last post was from harry himself,how did he know we were discussing his lap timer?

Harry has a Google Alert defined That pro-active support

- Harry