Parts list1 x 2K2 Resistor
2 x 4K7 Resistor
1 x 10K Resistor
1 x 2N222A NPN transistor
1 x USGloblSat EM-406A GPS module
1 x USGloblSat header cable
(Got both of these items from from Starlite-intl) otherwise you can get them here if you live in Australia.
1 x Hammond Miniature ABS enclosure P/N: 1551RFLBK or 1551RK
1 x Nikon 10 pin connector DIY cable
(Got mine from Stellardesign on ebay)1 x Hot shoe (pc sync port) adapter
1 x Veroboard
1 x length of ribbon cable. had some lying around.
1 x heat shrink tubing, small ones. had some lying around
1 x 40 way header pin
Tools Required- soldering iron
- dremel
- wire cutters
- pliers
- solder
- voltmeter
- Power supply

GPS circuit diagram - click for larger view
Testing on breadboard
I tested the circuit design on my breadboard and made sure that it was working correctly before building it on veroboard. Once the red LED starts blinking you are in business.
To simplify the build I laid it all out on graph paper before soldering anything. I worked out exactly where all the components, links and cuts had to be. I also measured and cut the veroboard to size so that it fits into the case. I also notched out on diagonal corners so that the veroboard fitted around the column where the top lid screwed into.
GPS module interface to Nikon D700 completed
Once I am happy that everything fitted correctly then I start soldering the components together. Double checked everything has been done correctly and when you are confident that all is 100%. You can plug the 10 pin connector into the D700 and you should start seeing the GPS symbol blinking on the top panel.
Top view of completed circuitVeroboard with the level converter circuitry, Nikon 10 pin connector and the 2.5mm stereo jack all wired up. Ready to be mounted into the case.
2.5mm Stereo jack connection to Nikon 10 pin connector
Close up of the 2.5mm Stereo jack and Nikon 10 pin connector. I also made sure that all soldered wires were heat shrunk to eliminate any short circuits.
Connect the following wires on the 2.5mm stereo socket to the Nikon 10 pin connector.
- Red wire - auto-focus - Pin 9
- Orange wire - shutter release - Pin 4
- Yellow wire - ground - Pin 6
Side view of circuit
Close-up of the level converter circuitry. It converts the 3.2V signal from the GPS to 5V for the Nikon D700.
Hole for 2.5mm stereo jack
Hole drilled for the 2.5mm stereo jack. Required for remote shutter release. Do the drilling at the lowest possible torque.
Top view of inside of case
Removed pcb support as it gives extra clearance (height) so the GPS module can fit in. I used the Hammond Miniature ABS enclosure P/N: 1551RFLBK, you should get the one without the flange 1551RBK!
Nice job
Cable relief
Cable strain relief for Nikon 10 pin connector. I used my dremel to ensure a snug fit. Take your time.
Tight fit!
All snugly packed into the case. This is where I plugged it into the D700 for the final test before screwing the lid on.
Hot shoe adapter - pc sync port.
I wanted to have the GPS unit mounted on top of D700. To achieve this I bought a hot shoe adapter off ebay.
Hot shoe pulled apart. Only held together with two screws.
We are only interested in the bottom half.
The plan is to cannibalise it just for the base. I made sure that it could be pulled apart before I bought it. It involves removing 2 screws which takes less than 10 seconds.
Top view of hot shoe
I cut a piece of scrap veroboard, using my dremel, and glued it onto the hot shoe to make a platform. I can now use glue, velcro or double-sided tape to attach the hot shoe base onto the GPS case.
The Finished Product Check-out part 1 of DIY GPS Project.