Best way to run OBD II and BT GPS at the same time

[ckowalc]

I'm trying to figure out what is the best solution I have for using BT GPS and collecting OBD II data.

Here is the equipment I have currently:
iOS iPhone 5S (jailbroken)
RoqyBT7/OBD7
Andriod Samsung Galaxy S3 (w/o cell service)
Qstarz 818XT BT GPS
ELM327 BT OBDII
iOS Harry's Lap Timer Grand Prix

Right now, using RoqyBT7 I can only connect to one bluetooth connection I believe. If that is incorrect someone let me know because the rest of this thread will be meaningless.

I'd like to collect 10 Hz GPS data and 4 Hz OBDII data. So here are some of the options I was thinking about:

1. Use HLT on iPhone w/ the BT GPS on RoqyBT7 and Galaxy S3 with BT OBDII using Torque app. Then merge the OBDII data into the HLT data afterward. Seems like a hassle but no purchases necessary.
2. Purchase BTstack for $5 (which has the capability of multiple BT connections I think?) then use HLT on iPhone w/ BT GPS and BT OBDII using BTstack.
3. Purchase WiFi ELM327 OBDII for ~$18 then use HLT on iPhone w/ BT GPS on RoqyBT7 and Wifi OBDII.
4. Purchase HLT GP for Android for ~$19 then use HLT on Galaxy S3 w/ BT GPS and BT OBDII.
5. I think other options are too expensive to be considered.

One thing that was concerning to me was, using HLT, the BT OBDII was running at 1 Hz when I used it with Torque on the Android it was at 4 Hz. Do I need to adjust my settings? Is this being limited by RoqyBT7 or HLT?

[Harry]

I cannot comment on most if the items. On track operation is sensible enough to encourage the use of pre-tested and frequently used solution...

For BTStack and roqyBT, please contact these guys - they know a lot more about potential side effects and options. #1 will not work - fusing sensor data is non trivial as you need too interpolate one stream to another. On update rates: one can count complete sets of PIDs as one fix, or each PID individually. LapTimer does the former. So 1 Hz in LapTimer means 5Hz for other measurement methods. Torque is a nice tool but I'm not aware of any method generating higher update rates than LapTimer does. It is extremely optimized - in particular for CAN busses.

Harry

[ckowalc]

Thanks for the quick reply Harry.

I think I understand what you are saying about the update rates. I could have been pulling only 1 PID (RPM) when I was looking at the Torque data and 4-5 PIDs on HLT.

It seems like the most reliable solution would be to just switch over to Android (Galaxy S3). I assume this would also be the most tested and frequently used option? Is there a way to transfer the app purchase from iOS to Android? How confident are you that the S3 could keep up with 10 Hz GPS and 5-10 PID/sec?

[Harry]

Probably the best solution (and supported ). I use the S3 (not the mini please!) for testing regularly but have not too much experience in real life. As long as your car does not have a Can bus, load from OBD will be small and BT bandwidth is no issue for two 10 Hz devices. Adding video may kick in - but that needs to be tested.

There is no one to one transfer from iOS to Android - Apple and Google want to be involved. For the part I receive, I offer a small refund as described in www.gps-laptimer.de / LapTimer Products / Mover Support.

Harry

[ckowalc]

Ok cool. I will be using it on a 2005 Honda S2000 and only 06+ has CAN bus so should be good there. Video will be recorded with a GoPro so shouldn't have load from there.

Sounds like I have a plan.