Harry's GPS Suite Forum

I use LapTimer GrandPrix v24.6.3 on an (old) iPhone 4S running iOS 9.3.6 with a Dual XGPS160 to capture lap times only (i.e., no video, no OBD). It's there for redundancy and so I can view the lap times during the event, the primary being a RaceCapture Pro recording to SD card (I find the RaceCapture app essentially unusable for things like that, LapTimer good!).

Yesterday LapTimer was failing because, in addition to connecting to my Dual XGPS160, it was also connecting to someone else's RaceBox (Mini, IIRC) ... even though the only device paired on the iPhone was the Dual XGPS160 (and, in fact, I think it was the only BT device found/listed). I don't understand how that can even happen, but that's not the issue. #;-)

Even worse, the RaceBox was given "priority" so it was ignoring the Dual XGPS 160. Seemingly, once we left the staging area and the distance killed the BT signal, LapTimer appeared to be quitting ... whatever the behavior, zero sessions/laps were recorded until it seems the person with the RaceBox left (or maybe turned it off if my LapTimer's connection was causing it to fail for him/her).

QUESTIONS
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Is there a way to configure my version of LapTimer to _only_ connect to a specific device (or a specific class of devices that could help reduce the likelihood of such issues)?

Is there a way to kill such a (RaceBox) connection from within LapTimer, when it occurs?

(For bonus points [I'm a retired software developer]) How was LapTimer able to connect to a BT device that was not specifically paired (and not listed as paired) to my phone ... this seems like a significant security issue (in general terms)?

Any help you can offer with this would be appreciated.

There are two types of BT connections made: one using BT SPP requiring pairing, and one using BT Low Energy - which does not require pairing. The Mini is using the later and LapTimer will connect to it when it finds one.

LapTimer will not connect to another GPS if a GPS is connected already. However, it can happen, that the connection to the first GPS drops shortly and LapTimer will connect to the second.

Workaround: there are various options. You can disable BT LE connection making altogether in Expert Settings (same for other types). You can limit connections to a single sensor type by setting a name filter in Expert Settings. And you can disable connections to individual sensor types by long pressing / swiping the respective entry in Sensor List and selecting Disable.

Silly me, on the "Sensor List" screen, I'd tried tap, double/triple-tap and swipes but didn't try a long press.

Thanks for your explanation. My gut-level feeling says that Bluetooth LE poses security risks in various scenarios, but that's not the topic, here.

After trying dozens of setting combinations, I found:

- "Mfi" must be on

- "Use Bluetooth LE Sensors" can be off

- any and all the name filters I tried, which were always warned about correctly in the "Sensor List" screen, eliminated the Dual XGPS160 ... I tried:
* the full name shown in the Settings --> Bluetooth screen (XGPS160-458E3D)
* the full name shown in the "Sensor List" screen when it was connected (Dual XGPS GNSS)
* Dual
* XGPS
* Dual XGPS
* XGPS160
* dual
* xgps
* dual xgps
* dual xgps gnss
... and some others. I often kill/restarted LapTimer and normally pressed "Refresh" on the "Sensor List" screen.

I postulated that the logic might be reversed and that any name filter removes, rather than allows, the named device(s) so tried "RaceBox" but that also eliminated the Dual XGPS160. At that point, I tried just "a" and just "X" then, since this was now over 30 minutes of testing, I gave up.

What name(s) should work to limit the device(s) recognized?

That’s the problem with Expert Settings - they are not documented und should be used when advised by myself only.

Try “Accessory”, this will limit sensor to all Mfi devices. These are safe because they will always use a pairing front up.

Harry

Thanks, Harry.

I'd ended my exploration of the "Accessory Tweaks" section of the "Expert Settings" with only "Use Mfi Accessories" enabled and all others disabled and with no entry in the "Use Sensors Containing Name" setting. Good to hear that will require devices to be paired with the iPhone.

As always, appreciate the excellent support, not to mention your excellent software. Hope you have a great summer.

This "RaceBox" issue happened to me last time at the track and I'm also looking for a solution.

I have a Dual XGPS160 and so I have to enable "Use Mfi Accessories".
Also, I have a Kiwi 3 so I have to enable "Use Bluetooth LE Sensors".

Because I have two sensors, I cannot use the "Use Sensors Containing Name" filter.
Since LapTimer connects to "RaceBox" at the grid, I may not be able to use the long pressing option in Sensor List.

Any idea to prevent the "RaceBox" from being connected to LapTimer in this case?

Select the Racebox sensor entry in Sensor List (after switching to „All“) and disable it after long pressing (Android) or swiping (iOS) the row.

- Harry

Cool! I missed switching to All!
Now I disabled everything except Dual XGPS and Kiwi 3 OBD, so I no longer worry about it.
Thanks!