Hook up GPS device - Feature Requests - CHDK Forum

Hook up GPS device

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Offline pan

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Hook up GPS device
« on: 10 / April / 2008, 09:59:49 »
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If you can use the USB port to control the camera,
shouldn't it be possible to hook a GPS device
to this USB port and then put GPS data right into the
pictures taken?
If not directly into the picture just taken, maybe a small file
with the coordinates could be generated or appended to
and after downloading those could be merged.
The Canon EOS 40D offers to hook up a GPS device to an
overpriced battery grip, how about a cheap alternative?

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Offline DataGhost

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Re: Hook up GPS device
« Reply #1 on: 10 / April / 2008, 10:24:12 »
The USB port on cameras wasn't intended to act as a host, so support for that is unavailable and will have to be coded in software, if at all possible. That alone is pretty hard already, the GPS probably also wants power from USB and I'm pretty sure the camera does not supply that. Else you'll need some chip to act as a bridge between the camera and the GPS, but it still requires some coding into the USB routines, which isn't that simple yet.

Re: Hook up GPS device
« Reply #2 on: 11 / April / 2008, 03:01:16 »
I don't know if it is even theoretically possible to connect two non-host usb devices.
Why not do what I do... just record the track and 'sync' it with the photos using EXIF timestamps. There are a few programs that let you do this (I wrote my own for Linux).

Re: Hook up GPS device
« Reply #3 on: 11 / April / 2008, 06:53:38 »
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« Last Edit: 22 / April / 2008, 17:23:14 by Barney Fife »
[acseven/admin commented out: please refrain from more direct offensive language to any user. FW complaints to me] I felt it imperative to withdraw my TOTAL participation. Nobody has my permission, nor the right, to reinstate MY posts. Make-do with my quoted text in others' replies only. Bye


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Offline pan

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Re: Hook up GPS device
« Reply #4 on: 11 / April / 2008, 09:04:35 »
the GPS probably also wants power from USB
No the GPS is self powered (Garmin eTrex in this case).
The camera can receive commands from USB, so it should be
able to read the data stream, that a GPS device sends as well.

I indeed do geotagging with a seperate programe.
However it would be much easier if the camera did it itself.
It would remove the local time zone problem.
You have to set your camera to the local time, not UTC (GMT)
unless you want new year's firework shots from Sydney
to show up as shot on Dec 31 14:00 .

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Offline PhyrePhoX

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Re: Hook up GPS device
« Reply #5 on: 11 / April / 2008, 09:26:24 »
Quote
The camera can receive commands from USB

well, no. the only command that can be sent to camera is "currency ON" or "currency OFF". the camera itself or the script interprets the signal as a command. you can - in theory - code a morse-interpreter that will interpret short & long bursts of currency. this is already done in a few scripts by fingalo i think.
bottomline: communication via USB port is impossible - right now.

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Offline pan

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Re: Hook up GPS device
« Reply #6 on: 11 / April / 2008, 10:22:14 »
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The camera can receive commands from USB

well, no. the only command that can be sent to camera is "currency ON" or "currency OFF".
bottomline: communication via USB port is impossible - right now.
This is a surprise to me,
since there are powershots like the A95 that
accept setting of the internal clock, startup
pictures/tones and a few hundred more things
via USB.

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Offline whim

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Re: Hook up GPS device
« Reply #7 on: 11 / April / 2008, 10:28:43 »
Are you sure it can do that without proprietory Canon driver software (Canon SDK)
that would highly surprise me !

wim


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Offline PhyrePhoX

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Re: Hook up GPS device
« Reply #8 on: 11 / April / 2008, 10:46:15 »
what whim said.
the "logic" behind the usb system is not "decrypted" yet.

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Offline whim

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Re: Hook up GPS device
« Reply #9 on: 11 / April / 2008, 11:10:07 »
@PhyrePhox
@pan

I just remembered this remote control program: PSRemote - Canon PowerShot Remote Capture Camera Software (downloadable shareware)
I once installed it to take a look (wasn't that great) but the interesting thing is, it's obviously made
with Canon SDK, and has all the SDK distributables on board. A lot of those are DLL's which makes
it fairly easy to spy on what functions they provide, for instance with DLLEXP (attached).
There's a couple of EXE too, IIRC, but those could be inspected with IDA, I guess ?
I'm pretty surprised, in fact, considering the amount of interest in Remoting, that nobody checked
out this route yet, AFAIK.

edit: aargh... forgot to attach
edit2: spelling  :D

wim
« Last Edit: 11 / April / 2008, 11:13:48 by whim »

 

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