Harry's Lap Timer

[fvee62]

I just read an article in Classic Motorsports about the Harry's Lap Timer app for a cell phone. It appears to co-ordinate lap times with your (iOS) phone's video camera. There was also a reference to data logging, but it wasn't clear how the data was accessed (by external sensors or some other means hooked up to the phone?).
I would like to be able to access traction circle type data for my performance in the turns and would like to be able to review the data after each session at the track.
Does anyone in the Vee community have any experience with this set-up and could give me some advice on it?
I looked in the Data Acquisition area on Apex, but didn't see anything there about this.

[mikey]

Here's what I know about it:
It was designed with HPDE in mind, for cars. It relies upon the iPhone internal accelerometers and GPS. It can also take an OBDII data stream input from modern cars so you can have more data. It does not use any other external sensors that I am aware of.

It's a great value for the money, but limited in accuracy. The track maps don't always come out accurately and the data sampling rate isn't that fast.

AIM is about the best value you can really get if you want to actually analyze data. You can sync data to video from separate sources using software like DashWare.

[DanW]

I've had Harry's Laptimer - Petrolhead for a long time. It works really well, pretty simple. The important part is secure mounting in the car, it will even take video with iPhone or android.

I've used it for track days in a road car (shhh, don't tell my wife).

Sampling rate on Petrolhead is 1HZ, which is a bit slow. However the "Grand Prix Edition" does provide for 20HZ support with the newer phones, YMMV depending on your phone. Mounting is important, particularly if you want to take video and overlay. It can also record video from a go-pro or sony action cam via bluetooth, then overlay data for review.

Harry's put up a lot of great documentation, FAQ's, and a forum.

http://www.gps-laptimer.de/documentation

Regards,
Dan

[Stumpthumper]

Just to chime in here, since I use Harry's for AutoX. Harry's will accept an external GPS antenna and it's recommended. For G loads, etc, it does rely on your phones internal accelerometers, which means the phone needs to be secure. I haven't spent too much time trying to calibrate mine yet, but in my miata all the roll causes inaccurate readings here. A tight formula car may not have that issue.
For the money it's certainly worth playing with.

[fvee62]

Thanks for the info everyone. I didn't realize the smart phones had accelerometers in them and that's how the data is gathered.
I will try playing around with it.

[mikehinkle]

I bought a older IPhone just for the purpose of running harry's in my vee. I also bought a ram mount like this one.
http://www.summitracing.com/parts/rmi-3008/overview/
Holds the phone perfect. I only used the internal GPS to test how I liked it in the car. The lap times were about .1 off from lap times recorded with the MyLaps transponder. I uploaded the data from harrys to my computer which matches it to Google maps and the data was useless because of the GPS accuracy. I'm sure it would be better with a external GPS but I have not gotten one yet. If I had a choice I would go with a AIM system but for less then $50.00 it cant be beat for in car lap times.

[TE37]

can a smartwatch be worn/used while on the track instead of having to have a phone in the car?

[holmberg]

Harry's laptimer also supports external data gathering via RaceCapture/Pro from AutoSportLabs. You can see here that there are many hard-wired sensors you can add to this. This device also has more accurate GPS, accelerometers, and gyros.

I don't know how much of the additional sensor data can be displayed or analyzed in Harry's Laptimer. They suggest that data can be analyzed to some degree on a tablet (probably an iPad, since they haven't optimized the screen layout for Android tablets yet), but more fully on Windows with with Circuit Tools from VBoxMotorsports.

AutoSportLabs also has their own phone/tablet apps for use with RaceCapture/Pro. They say they're working on adding more analytic features. They also say you can analyze it with GEMS Data Analysis software on Windows.

Note, I haven't tried any of this myself. I'm just looking into it too.

[MotorCade]

I used Harry's lap timer to capture this video of a track record at Buttonwillow. Video quality is meh, and mount is very shaky. But I don't blame the app for that. I don't know which version this was, my best friend had it on his phone, so that's what we used.

https://www.youtube.com/watch?v=zpHpIY6z9Hg