External GPS dilemma.

Discussion related to external and internal GPS / GLONASS / Galileo / BeiDou sensors
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DrPhyzx
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External GPS dilemma.

Post by DrPhyzx »

So, I'm looking to buy an external GPS receiver for an iPhone 3GS to use with Lap Timer. I would pick up the Emprum UltiMate in a hot second except for the following.

I use the Apple AV cable (30-pin on one end --- USB + composite A/V on the other) to break out the audio from the iPhone to feed to the stereo. The OEM stereo/nav does not have iPod integration but does have composite A/V inputs along with a power source inside the center console armrest as well as Bluetooth for calls. Together with a Proclip mount with 30-pin passthrough and a USB lighter plug, it makes a nice package: I just slide the phone in/out and it's all set for power, music, calls and a nice mount with all cables hidden inside trim.

If I get the Ultimate, I can't use the mount, and I can't use the stereo when accessing the GPS without building a custom cable to split out the audio upstream of the UltiMate. I was hoping the signals on the USB bus were a direct mirror of those on the USB section of the 30-pin: that would allow me to connect the Ultimate to the USB connector at the other end of the Apple A/V cable. However, Roger has indicated to me (via email) that this is a no go.

So... as far as I can tell, I have to go with Bluetooth. I wouldn't mind that, but Harry's most recent words on getting 5Hz with the XGPS150 haven't been encouraging. If I really thought it was coming soon (e.g. this year), I would gladly wait, but I've heard no guesses about that.

So... ideas or advice? I was initially tempted to try the UltiMate to iPhone via the USB connector on the UltiMate, but now that I think Roger has clearly understood my question, it seems clear that won't work.

BTW, in case you were wondering why I would want music while using Lap Timer, let's just say I have a very interesting commute.
hms
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Re: External GPS dilemma.

Post by hms »

I have asked Dual twice on their forum for when the 5hz update is coming.
In both cases the moderators have seen not fit to release the question onto the forum or provide any response.
My only supposition is they can't be bothered, not good, or there is some form of non disclosure agreement from Apple about this, also not good.
Gives me the impression it will not be happening!
H
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DrPhyzx
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Re: External GPS dilemma.

Post by DrPhyzx »

hms wrote:I have asked Dual twice on their forum for when the 5hz update is coming.
In both cases the moderators have seen not fit to release the question onto the forum or provide any response.
My only supposition is they can't be bothered, not good, or there is some form of non disclosure agreement from Apple about this, also not good.
Gives me the impression it will not be happening!
H
Thanks. I agree it smells funny. I also asked the question and it didn't end up on the forum. Very annoying, but at least they are getting the message.

On the UltiMate: I really don't see why the protocol on the mini-USB connector should be different than on the USB bus of the 30-pin, but I suppose it could relate to some requirement of how USB communications to the iPhone work. Has anyone ever tried plugging the UltiMate into their iPhone using a sync cable (plus a USB to mini-USB cable or adapter) to plug into the USB side of the UltiMate?
Emprum
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Re: External GPS dilemma.

Post by Emprum »

Regarding the UltiMate GPS, when plugged into the iPhone it will allow normal charging and syncing over USB.

The easiest solution to the problem at hand is to use a (short) dock extender cable between the iPhone and the UltiMate GPS and then wire out the audio and video connections from that extender cable. But note that Apple's A/V cable might need more than just those connections to work properly. So it's no guarantee video would work, but at least you would have access to audio.

Alternatively, you can use the headphone jack to access audio (not sure if you would really be able to hear the difference between the headphone jack and line out in the dock if you are on the road).

Instead of an extender cable, you could also open up an old dock (which has an output and input similar to an extender cable). But here also you will need to check what wires are connected and which ones not; I don't believe all 30pins are routed through in the dock so it would require some soldering skills.

R.
DrPhyzx
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Re: External GPS dilemma.

Post by DrPhyzx »

Thanks Roger (again), I really appreciate your attempts to find me a solution!

Those are all OK ideas, but none are really great, IMHO. Making my own custom cable (30-pin to 30-pin + A/V) would be the neatest of those, but considering how little sleep I get already, it's not a great solution for me, even though I have the skills and resources readily available.

Here is another idea I should have thought of before. What if I did the following:

iPhone 30-pin connector <-> Apple A/V cable (30-pin to USB + A/V) <-> Female/Female USB adapter <-> iPod synch cable (USB to 30-pin) <-> UltiMate 30-pin connector

That should preserve the data path that the UltiMate expects to the iPhone through its 30-pin USB bus connection.

Would that work??

-Tim

Edit: Aargh... the last connection listed is male-male. I really need to get from Female USB to Female 30-pin: so far can't find that...
DrPhyzx
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Re: External GPS dilemma.

Post by DrPhyzx »

OK, now I think I'm getting somewhere. How about:

iPhone (female 30-pin connector) <-> Apple A/V cable (male 30-pin to male USB + A/V) <-> Belkin Shuffle dock (female USB to female 30-pin) <-> UltiMate (male 30-pin connector)

Belkin Shuffle Dock (for 1G shuffle: hard to find, unfortunately):
http://www.belkin.com/IWCatProductPage. ... _Id=258633#

I believe all of those components pass through all signals needed by the UltiMate. Then I can plug the USB side of the Ultimate into my charge cable, and I'm pretty sure the Ultimate is going to work fine inside the armrest, which is just thin plastic. If not I can locate it pretty much anywhere I want (within reason) by extending the USB.

Worth a try? Comments? I guess if the UltiMate uses something other than the USB data bus to connect to the iPhone, this won't work still.
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