For Autocross: Vbox Sport + BT1 or Vbox Sport + GL1 ?

Discussions on all kinds of sensors (GPS, OBD, video/audio) and other accessories like mounts
Metalgearsolid_x
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Re: For Autocross: Vbox Sport + BT1 or Vbox Sport + GL1 ?

Post by Metalgearsolid_x »

chknhawk wrote:I am using the gl cable with adapter on my iPhone 5 and using internal gps. Mine seems to be working very well. I would upload a video but I'm on my mobile. Here is a YouTube link. Tell me what u think.
[youtube]http://www.youtube.com/watch?v=qnkrPrQB1yU[/youtube]
Looks awesome. I think GL1 provides a lot of the data and iphone 5 gps is much smoother. I have also noticed that it's (video) your iphone camera overlay, am I correct? I'm pretty much 90% with the iphone overlay synchronization. I think one more day of tweaking (I wanna try .4 and .6s) and I should be fine. The problem I'm having is overlaying gopro video and logger data. I need to synchronize GPS and obd data perfectly.

Nice run BTW :D
chknhawk
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Re: For Autocross: Vbox Sport + BT1 or Vbox Sport + GL1 ?

Post by chknhawk »

Yes, iPhone overlay in the corner. Came out sideways. The sync seems to be perfect though. The data logging through the cable has always been near real time even in other apps. Good luck!
chknhawk
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Re: For Autocross: Vbox Sport + BT1 or Vbox Sport + GL1 ?

Post by chknhawk »

Nice run! I think that is the longest AutoX track I have ever seen! the data is a bit sluggish for me personally. I don't know about the breaking data but it should be able to pull that and overlay it... As far as setting up short sprints or whatever I have a couple set up on mine. I think I had to define a start point and stop point.. Say you want to test run/lap time your commute to work. You could just tap autocross then set the start point and set the end point. Any time your driving with lap timer on it "should" start recording as soon as you cross the start point no matter what is happening. Mine does it sometimes when I get near my office. I guess I set a POI for laptimer at one point and now it is stuck in there forever. GL!
Metalgearsolid_x wrote:Hi Harry,
So I went to my first autox with GL1 and XGPS160 setup. XGPS worked fine but the OBD was troublesome. However, I made a mistake. I know you wanted me to bring the OBD delay value to .5 from 1s. I "thought" I did that but in reality I didn't :(. So this video WAS shot with 1s delay on OBD. But there were other issues that I want you to see:

[youtube]http://www.youtube.com/watch?v=iELEOF1k7bU[/youtube]
Video shot with GoPROHD 2 and HLT (GP edition) + Xgps160 + Go Point GL1 overlayed with Racerender 2 (trial)

a. Why does my G-meter is so slow or doesn't move heavily with vehicle momentum/braking.

b. Why does my gears go from 1-2 and then drop back to 1 (toward the end last 10 sec or so). I def was driving 2nd gear.

c. why did the RPM buried toward the end?

d. how come I never get brake red on screen?

I have changed OBD delay to .5 now. Next event on 24th. I'll test it out. It should be better.


===================================================================================================

As for video overlay with videos shot with iphone camera, I think your suggestion worked MUCH better than first post. I dropped it down to .5 second on video overlay synchronization. Take a look:

http://youtu.be/uXeoj7Vrh1c
Xgps160 + OBD GL1

Anything else I can fine tune? (.4 or .6 on overlay synchronization or you're happy? Still, would like to see brake red when I brake.


Also, one last question, How do I start recording without being at track or autox event? Let say I want to record from my home to work. I want to use go pro HD and use harry's laptimer to create a (or multiple) run (s). Where do I go? If I can record randomly driving, I can fine tune or test out more things etc. Please let me know. I'm asking for recording without using iphone camera. Just random recording with gopro and hlt. Later I can overlay with racerender.
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Harry
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Re: For Autocross: Vbox Sport + BT1 or Vbox Sport + GL1 ?

Post by Harry »

Harry wrote:One thing I can do is have a look into the LapTimer data used for this video to verify data is o.k. So if you want, expert this exact lap to .hlptrl and .csv and send it to Harry@gps-laptimer.de
Thanks for sending the data. Besides the mapping issues discussed, OBD connection is lost in the last third of the data sent. As the recording dates back to an earlier v17 version, both rpm and throttle are extrapolated to invalid values. The first 2 thirds look perfect and should give you a nice overlay (provided mappings are correct).

- Harry
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Metalgearsolid_x
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Re: For Autocross: Vbox Sport + BT1 or Vbox Sport + GL1 ?

Post by Metalgearsolid_x »

Thank you Harry. I think I'm getting better at it. This is the video from LAST autox event. It seems very fluid. I forgot what was my obd gl1 setting (I believe it was .5s) but video came out nice.

[youtube]http://www.youtube.com/watch?v=vziBO2pGY-M[/youtube]

Gopro hd camera
Metalgearsolid_x
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Re: For Autocross: Vbox Sport + BT1 or Vbox Sport + GL1 ?

Post by Metalgearsolid_x »

Harry,
Can you take a look at this one? I am using iphone 4s with XGPS160 for boost and GoPOINT GL1 connected OBD. I ran with .5s obd delay. But if you looks closely, you'll see it's (RPM) a little slower than speedo. Should I do .4s? thanks

DATA file:
Fastest time philly scca dover 9.15.csv
(148.53 KiB) Downloaded 175 times
Setting:
harry's laptimer.png
harry's laptimer.png (101.74 KiB) Viewed 5419 times
Video: [youtube]http://www.youtube.com/watch?v=RG4e80K_570[/youtube]
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Re: For Autocross: Vbox Sport + BT1 or Vbox Sport + GL1 ?

Post by Harry »

Please export to .hlptrl/.hlptrz, that is easier to analyze.

- Harry
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Metalgearsolid_x
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Re: For Autocross: Vbox Sport + BT1 or Vbox Sport + GL1 ?

Post by Metalgearsolid_x »

Harry wrote:Please export to .hlptrl/.hlptrz, that is easier to analyze.

- Harry
LapTimer-0010-20130918-025346.hlptrz
(31.62 KiB) Downloaded 190 times
here you go
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Re: For Autocross: Vbox Sport + BT1 or Vbox Sport + GL1 ?

Post by Harry »

Topic #1 - sync between GPS and OBD speed

Please note all of my statements below are based on the assumption the recording you sent has been recorded using exactly the delays shown in your snapshots above!

From the first snapshot you can see GPS and OBD speed are shifted on the timeline and not in sync...
iOS Simulator Screen shot 18.09.2013 19.32.23.png
iOS Simulator Screen shot 18.09.2013 19.32.23.png (81.33 KiB) Viewed 5404 times
In Grand Prix a cursor is available to see the details, I choose one peek:
iOS Simulator Screen shot 18.09.2013 19.32.42.png
iOS Simulator Screen shot 18.09.2013 19.32.42.png (96.72 KiB) Viewed 5404 times
and the corresponding peek for OBD
iOS Simulator Screen shot 18.09.2013 19.32.47.png
iOS Simulator Screen shot 18.09.2013 19.32.47.png (96.35 KiB) Viewed 5404 times
Time gap is 0.7 seconds and OBD is late... This means you need to increase the OBD delay as it is obviously coming in with a bigger delay than expected (0.5s). So setting "Any OBD" to 1.2 will do the job for the next recording. As an alternative, you can decrease GPS delay - which is my recommendation as the XGPS's default is 0.7 anyway. So any OBD = 0.5s and XGPS = 1.5-0.7 = 0.8 should be fine.
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Re: For Autocross: Vbox Sport + BT1 or Vbox Sport + GL1 ?

Post by Harry »

Topic #2 - sync between GPS and Acceleration

Without adding additional snapshots, GPS speed and lineal acceleration synchronization can be done in the same way. Increasing speed means positive lineal acceleration (>0) and decreasing speed means negative lineal acceleration. Comparing one speed peak (lineal acceleration) with lineal acceleration passing the zero line shows acceleration is behind GPS too. This means acceleration needs to be increased or GPS decreased. As we have seen it makes sense to decrease GPS delays anyway, reducing GPS delay to 0.8 will compensate part of the acceleration gap. The gap I measure seems to be bigger than 0.8, so acceleration delay needs probably an increase on top.

As the golden rule is to not change two items without testing the first change, I'd suggest you try the GPS delay reduction first and check if things look fine afterwards. In case they do not, check speed sync for GPS and OBD first and adjust acceleration next.

Once this is done, you have perfect sensor synchronization. As a last step use a video overlay to check if sensor to video is fine too.

- Harry
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