Re: Nikon D200 / D300 and GPS



Richard H. wrote:
Chris W wrote:
I found a web site a while back (don't have the link anymore) where they showed how to make your own cable to hook your GPS to the camera. Seems all the $100 cable does is us a $2 chip to convert the serial level RS-232 signals to TTL level. Well I have found a GPS that has TTL level output along with the serial level signals. My question is, is there a way to pull the power the GPS needs to run from the camera? The GPS spec *** says it needs 45ma at 5V. If I can avoid making a battery pack for the GPS, that sure would make for a nice very small and simple solution to having a GPS on the camera instead of having it in your pocket with wires all over the place. The GPS is only 41mm square and I was thinking of making a hot shoe mount from some old dead flash.

Hi, Chris.

Yeah, that connector seems to be proprietary, and they're proud of it. Even the 3-wire version with only bananna-plugs on the end is expensive.

Don't try pulling that current through the 10-pin port. There's no way it's rated for 45mA; if they haven't current-limited it (they should have) you'll damage the camera. Maybe wire to the camera battery contacts?

Personally, I wouldn't hack on my expensive camera, and I don't like making the camera bigger (or adding external wires) unless it really needs it. Why not sync the GPS data to the pictures in post-process instead of real-time?

The cheapest candidate I've found so far is the Garmin eTrek H (~$100) will do ~12 hours on a set of AA's and supports serial downloading with an add-on cable. You'd need to code the script to load the EXIF data, but it's about half the cost of Sony's GPS photo gadget. Haven't had time to hack out this project yet, but it's high on my list.

I am curious, though - what GPS module did you find in that size?

Cheers,
Richard

p.s., speaking of adding dangling wires to the camera, I find it a bit ironic that Nikon's D300 wireless module (WT-4a) is a brick with a cable to the camera. :-) I thought the D200 style (in the battery grip) was a lot slicker.


Here is the GPS.
https://www.argentdata.com/catalog/product_info.php?cPath=23&products_id=23

After further research it seems it has 3V TTL levels and the camera wants 5V so I will still need a converter. Also it seems this guy...

http://forums.dpreview.com/forums/read.asp?forum=1021&message=18460359

has powered his from the camera but it is unclear where he is getting the power... I think it might be from the hot shoe.





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Chris W
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