Hi. I might be asking for the impossible here! I have an app called memory map which provides OS topographical mapping in the uk (amongst other places). It works very well and in fact can log trips (long runs and bike rides) using the internal gps even with the iphone (3g, jail broken using os4 with multitasking enabled) autolocked. Problem is this eats the battery. I thought a solution might be to use btstack gps to connect to an bt gps and share the battery load. This works wonderfully with btstack gps working in the background until the iphone either does an autolock or you press the sleep button. Memory map continues fine but btstack appears to freeze up- you can tell this as the time output freezes at the last output before the autolock. When the iphone is "woken up" I have to do a disconnect of the gps and reconnect to get a fix- it does not reconnect by itself. I have tried this with btstack as the only active app and still get the same problem. Should this be happening? Better still, should the btstack gps be able to maintain an active connection to the gps with the iphone in autolock?

Failing that can you think of an app that will kill the screen (rather than manually dimming to max) to save the battery without putting the iphone into autolock?

Sorry - so many questions, and thanks for all the hard work and support you clearly give!

hi. BTstack GPS does not prevent the iPhone from sleeping. I thought about that, but I figured it would be the task of the app using (BTstack) GPS, as it has to do this already for using the internal GPS. Or is there a detail I'm missing.

Other than that, I got told that the code to stop iPhone from sleeping from Insomnia code code project doesn't work on 4.0 anymore.

Yllier made a "ScreenDimmer" package that mighe help you a bit.

Thanks for the response.

I don't know if this is specific to the Memory Map app, but whilst it remains active even whilst the device is aspleep, it does not seem to keep btstack in the same state. When using the internal gps Memory map is able to track courses with the iphone apparently asleep.

I have found a work around of sorts though. If the ipod is turned on - a tune or playlist selected and put on repeat and the volume is put to zero, the iphone can be put to what appears to be asleep (is it actually asleep when the ipod element is playing - probably not) without an issue. Using my iphone 3G like this with 3g & wifi services turned off and turning the screen on to check where I am very infrequently I can log my course for about 15% of the battery life per hour which is not too bad at all - significantly better than using the the internal gps and much more accurately. I guess the ipod function must be using some battery life which would be nice to sort out eventually.

Thanks again.

Insomnia works for ios4 now. http://www.ijailbreak.com/cydia/insomnia-pro-v4-0-2-adds-ios-4-support-keep-wifi-connection-alive/

I just confirmed insomnia fixes the problem, I can make a video if need be. I am on 4.1. It does work. No FREEZE! YAY. Get insomnia until dev fixes this issue in house.

Since the December 2010 update of BTstack, all connections are dropped and a low power mode is set for Bluetooth. It doesn't freeze anymore.

yeah insomnia now work for ios 4 now check it out here http://www.unlock-iphonesoftware.com/insomnia-pro-v4-0-2-%e2%80%93-adds-ios-4-support-keep-wifi-connection-alive/