[SOLVED] OBD WLAN dropping. Using w/Jailbroken ...

[Harry]

Hi Ben,

Tested it today with an old iPhone3G - same symptoms. As the iPhone3G has definitively a different WLAN implementation, I doubt it is a pure hardware issue. It is either in the iOS's or the dongles WLAN software stack, or it is triggered by a special communication pattern implemented in LapTimer and other OBD apps. The last point is a good one, will try to set this test case up next weekend (i.e. my MacBook running the simulator, connected using an ad hoc network connection to the Kiwi).

- Harry

[ben]

I'd also try minimizing the data that is collected, perhaps only getting data from a point or two at infrequent intervals (e.g. collect RPM once per second, speed once per second).

[KrisS]

Using AT commands I increased the timeout to the maximum possible value and shortened the "keep alive" connection parameter on OBDLINK.

ATPP 03 SV FF
ATPP 03 ON
ATPP 17 SV 10
ATPP 17 ON
ATZ

It works the same though (breakes connection in more leess same intervals). Seems more complex issue then.

The Wifi in OBDLINK seems to be using this wifi modele

http://www.rovingnetworks.com/products/RN_131

[ben]

I did some testing today with my PLX Kiwi and as I suspected and mentioned before in the thread -- it looks like the OBD WLAN devices are just getting 'overloaded' and entering some sort of 'reset'. Not sure if this is related to the OBDII side of things, or the Wifi side of things.

In any case, some changes to OBDII polling in Laptimer at some point in the future should do the trick.

On a related note, I bricked my OBDKEY WLAN trying to set it to join an access point mode, so be careful with your AT commands Kriss. They all seem to use some version of the Rovingnetworks wlan/serial devices.

[KrisS]

I'm trying to be carefull...

As my obdlink works with USB and Wifi I tested both and did not see any issue on ODB command level with my car.

Then while trying to connect via Wifi I've spotted that the channel for adhoc network is 1st channel. In my neighborhood most of the Wifi Devices are on 1st or 11th channel. And that might be the reason (same WiFi channel conflict ?) for Wifi connection dropping in city. When you are in middle of nowhere and there are no other devices on that channel it works fine (based on others experience).

Tried to check it (by changing channel) and looked into wifi document from roving networks. It seems that all the parameters including channel and other parameters can be changed "easilly". The bad message is that OBDLINK does not want to help configure network as this is "not their product". The Customer Support is something they do not obviously understand.

Downloaded terminal program as indicated in the documentation I cannot enter configuration mode (although all other AT and ST commands work fine). After sending $$$ on the prompt I should get CMD answer but so far no succes. If somebody can help me how to configure the terminal to be able to enter this mode I'm willing to risk a little.

[ben]

Kriss, try sending it a 'get ev' command after entering command mode, does it return anything?

[Harry]

Hi,

I did extensive changes to LapTimer's OBD integration, and did trial & error on all kinds of OBD settings this weekend. Although I'm not finally sure if thing are fully fixed, I come back from a longer drive (> 1h) without any drop. The setting I have most evidence currently is 'adaptive timing control' which is 'on' by default. Turning it off and setting the timeout to the max, seems to fix the dropping connection. The setting actually applied is

ATAT0
ATSTFF

I will further test and analyze, but wanted to give you a signal. As I changed quite a lot, it is always possible, the fix is coming from somewhere else... In case you want to help testing, have any OBD device available, and you are able and to willing to run some test cycles during the next 2 days, please contact me by sending your device's UDID to me.

- Harry

[KrisS]

I entered the values proposed by Harry. Will test it today and tomorrow on my way home and will check if it helps.

On Scantool.net forum the support told me that I cannot get to wifi while connected via USB as the WiFi is disabled then. If no improvement I will try to get to Wifi setting to change the adhoc channel to 2 or 3 as on 1 I have plenty of other devices that might be causing conflicts.

[Harry]

Not sure if the named settings will be reverted by the ATZ command LT issues just after establishing the connection. Send me your device's UDID if you want to test an early version. I changed the WLAN setting to automatic channel (i.e. 0), not sure this changed something in addition. I will reset this and remove all the other tweaks (like setting a router) to be sure the problem is really caused by the adaptive timing only.

- Harry

[KrisS]

Tested the settings but no change. I will send you my UDID from iTunes via mail . PW

regards

K