arckarts

Nikon GPS Adapter V3

Tested working with D200 and D800E

 

 

The original version of this uses an external GPS (Garmin eTrex) I’ve just changed it to use a small GPS module  from AdaFruit and a custom case created in SolidWorks and printed on my Thing-O-Matic. I’ve kept the original instructions so both versions are covered here.

 

Note: this needs basic electronic skills, if you don’t feel confident then please don’t attempt it. As it depends upon third party components and cables which may change in orientation and colour coding you should verify all connections and operation before connection to your camera.

 

I didn’t include an on/off switch in the printed version as I don’t believe it is necessary, I just unplug it when not needed.

 

The purpose of this project was to develop a way of installing a GPS on to my D200, mainly as an aid to my landscape photography database rather than for Geocaching etc. After researching on the Internet and judicious use of Google I managed to find the connection details for the 10-pin connector on the front of the D200. Despite extensive searching though I was not able to find out exactly what was contained within the Nikon GPS adapter. From other sites detailing hacks for the GPS adapter it looked like it contained an RS232 to TTL level converter (MAX232 or similar). Now, while it is relatively easy to do it this way it is still pretty bulky and uses several parts. As I was only interested in sending data from the GPS to the D200 then I just had to convert the RS232 level signals from the GPS NMEA 0183 output to the TTL level input of the D200. To achieve this I built a simple inverter using two resistors, general-purpose NPN transistor and a diode. Fig1

Schematic, fig 1

Operation

 

R1, 10K is used to drive the base of T1 from the RS232 level signals and ensures that T1 is fully turned on when the RS232 signal is high.

D1 protects T1 base-emitter junction from reverse biasing when the RS232 signal goes negative.

R2 is the collector load and is sufficient to pull the input of the D200 high when T1 turns off.

 

Parts list

 

R1-10K 0.25W Carbon film resistor

R2-4K7 0.25W Carbon film resistor

D1-1N4148 general purpose Si diode

T1-ZTZ651 or equivalent general purpose Si transistor

Heat shrink tubing

10 pin connector, Nova Photography  (http://cgi.ebay.com/Nova-Nikon-MC-35-MC-23-Type-10-Pin-All-Wired-Plug-Cord_W0QQitemZ330072469568QQihZ014QQcategoryZ64345QQssPageNameZWDVWQQrdZ1QQcmdZViewItem)

NOTE: This is no longer listed on eBay and may need some searching to find it. Sometime the shutter release cables advertised have all of the wires in place internally, but YMMV

GPS cable (supplied with GPS or get from eBay)

GPS –I used Garmin eTrex legend from Circuit City but any model with an NMEA output should work

OR

Basic GPS Module PMB-648 https://www.adafruit.com/products/272

There are many of these around and as long as it has a NMEA 0183 output they should work

Flash adaptor-buy from B+H, Adorama or local camera shop

Kapton tape

SuperGlue

TOM- Black ABS

4 x M3x10 bolts

 

 

 

How to do it

 

Note: This uses basic soldering and mechanical tool skills. If you don’t feel confident then DON’T DO IT! As usual there are no guaranties of any sort with this information, USE AT YOUR OWN RISK.

 

The flash adaptor

 

Buy any type of flash adaptor, usually used to give a cord connection for cameras that don’t have an external flash connector.

Drill a clearance hole through the centre of the adaptor for a 4-40 screw (or use M3 if in ROW)

Select a spot on battery cover of eTrex that enables the GPS to sit on top of the camera without projecting into your face when at eye level (see first picture).  Mark position and drill and tap a 4-40 (or M3) hole. Use a countersunk screw to fasten the adaptor to the eTrex. The rubber finish to the eTrex ensures a very secure fit. If you’re still concerned then use some adhesive as well. Take care that the screw does not interfere with the flash connections on the top of the camera.

 

OR

 

Print the case on your TOM

Insert the GPS module, note it’s a tight fit, you may need to trim the cavity to make it a snug fit. Use a dab of hot melt glue to support it if necessary.

GPS Module connections are available at

http://www.parallax.com/Portals/0/Downloads/docs/prod/sens/PMB-648_Specification_V0.1.pdf

 

Build the circuitry using ‘ugly’ construction (if I was doing this in bulk I’d make a pcb but didn’t feel the need for a ‘one-off’)

Be sure to keep total thickness of circuitry <2mm

Carefully wrap in Kapton, double check for shorts and opens

File matching areas in the top and the base to match the cable. I didn’t put this in the model as I wasn’t sure of the fit but very easy to do with a small file

May need to open up the holes in the base

Deliberately left the holes in the top snug so as to make them self tapping for the M3 bolts.

Check all of your connections

Glue the flash adapter to the base of the GPS module. I used superglue which works fine and it’s very secure.

 

Test

 

Before connection to the camera, connect a 5V supply and verify that the NEMA RS232 output is driving the transistor and that a 0-5V TTL level output is going to the relevant pin on the D200 connector.

 

When connected to the D20 the GPS indicator should flash to show that it is receiving data and then go steady when the GPS module has locked on.

 

Connections

 

I cut the cables to length so that the cables would fit around and under the lens as the eTrex connector exits to the left (when seen from the front) and the 10-pin connector exist to the right.

 

 

 

 

 

Build the circuit in fig 1 using ‘ugly’ in line construction (see images below) keeping overall diameter small so it fits within heat shrink sleeving. Attach the wires according to fig 1, note, this is the colour code on the connectors I had. Check first using a DMM!!

 

Cover the circuitry with heat shrink sleeving, ensuring that there is no danger of short circuits inside it, I sleeved most of the internal connections with small gauge sleeving as well.

 

I verified operation with an oscilloscope (see below) but as this is very simple it should not be necessary. Plug into D200, turn on GPS, ensure that NMEA output is enabled and the GPS indicator on the camera should start to flash. As soon as the GPS achieves lock then it becomes a steady indication.

 

Voila!  Enjoy!

 

Acknowledgements

 

http://www.hackaday.com/2006/08/21/nikon-d200-gps-adapter/

http://www.k-i-s.net/article.php?article=20

http://www.garmin.com/products/etrexLegend/

http://www.schneordesign.com/Avi/F100/diy_01.htm

http://www.perfect4me.com/Products/mynikon/default.asp

 

 

 

 

 

 

 

Images

 

Assembled device before heat shrink

 

 

After heat shrink applied

 

 

RS232 input (note +/- 3V)

 

TTL input to D200 (note 0 to 5V)

 

D200 cable, as supplied

 

Flash adapter on GPS, bottom view

 

Flash adapter on GPS, side view

 

Flash adapter on GPS, end view

 

 

 

 

Bottom view of GPS module in case with level convertor and kapton tape insulation

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Case bottom with gap for cable

 

 

 

Hot shoe mounted to case with SuperGlue

 

Another view of adapter mounted on camera