Wiring an underwater camera to external power?

I'm using a stereo pair of Nikon D5300 DSLRs in Ikelite housings for fisheries research in small, shallow (< 2 m) streams. I'm recording via HDMI to Atomos Ninja Blades, and I'm trying to figure out how to power the cameras for much longer than their usual battery life via the external power supply connector:

http://www.nikonusa.com/en/Nikon-Products/Product/Power-Packs/EP-5A-Power-Supply-Connector.html

and corresponding AC adapter

http://www.nikonusa.com/en/Nikon-Products/Product/Power-Adapters/EH-5b-AC-Adapter.html

I'd like to find a waterproof way to run power from a portable AC generator to the cameras, through the housings, to keep them on indefinitely. The waterproof part of the system needs to run at least 6 feet or so (to an extension cord above the water's surface).

Does anyone make any sort of generic bulkhead I could adapt for this? Is it possible to do this with some sort of epoxy instead? Does anyone know any resources or webpages that would be helpful for figuring out how to do this?

(On a related note, I also have to figure out how to circumvent the 30 minute "live view auto off" limitation. I'm currently thinking of using a tiny microcontroller and linear actuator to press the exposure compensation button inside the housing every 29 minutes, which prevents the auto off but does nothing else. I'd welcome other suggestions.)

I don't think you will find a lot of information on this on the net. Are you using the strobe connectors? I can modify things for you if you want and we can discuss it off line. I am in Cincinnati Ohio where are you?

Your business looks really interesting, Bill. I'll send you an email with some more details about this issue and some other things I'm trying to figure out for our system.

I'm not using the strobe connectors. I'm in Fairbanks, Alaska.

Yes,
soldering two special cables (one outside and obe inside the housing) using your unused strobe bulkheads should do the trick.

Otherwise have a fischer or similar connector mounted, any professional shop with a good drill or lathe should be able to drill the necessary hole.

Chris

This video might give you some ideas. It shows a Nikon D4 underwater housing fitted for external power, remote control, and Ethernet for use in the London Olympics:

It is possible to buy some of the wiring components from http://www.seacamusa.com/, see "prices" in menus.

I have used the SEACAM remote control components which use S6 connectors and cabling. The price lists indicate some new sizes but I have not seen any description of them outside of this video. S6 bulkhead fittings thread into the wall of a housing. I have seen S6 bulkheads with a nut so they possibly can be installed in an Ike housing with a plain hole. http://reefphoto.com/shop/ also makes and sells some S6 items. FYI S6 cables have 6 conductors.

Your business looks really interesting, Bill. I'll send you an email with some more details about this issue and some other things I'm trying to figure out for our system.

 

I'm not using the strobe connectors. I'm in Fairbanks, Alaska.

What I think would work best for you is to take the battery adapter and connect it to the ikelite strobe port. Then use a ikelite strobe extension cord (http://www.ikelite.com/accessories/4102.15-extension-cord.html) to get out of the water to the Nikon ac adapter with a ikelite strobe connection on it. This would give you proven watertight connections without modifying the housing. It would also allow you to dissemble the unit if needed without un-soldering things.

For your "keep alive" problem - Will a half press of the shutter do the same thing ? It would with a Canon so I'd expect the same with the Nikon. If that's the case, you could connect your microcontroller to the external shutter release connector and then you'd just need a transistor rather than an actuator and all the mechanics.

I agree about powering through the Ikelite strobe connector.

Since you mention using a microcontroller, does that mean you have the ability to get a custom pcb made ? I looked at doing something similar and was going to make my own PCB to go where the Ikelite one goes. That way you get the wiring to the strobe connector and power to your microcontroller and it's not rattling around in the box.

PCB's and microcontrollers are what I do, so it makes sense for me. It may or may not for you.

How are you getting the video out ?

Steve.

Thanks Steve. Great idea on the shutter release button. I just checked, and it does keep the view alive.

This would be my first time using a microcontroller, except for a couple days tinkering with an Arduino. I'm good with programming so I'm sure I can figure it out, but I very much appreciate any advice from someone with more experience. I don't have the ability to have a custom PCB made. My initial search for tiny programmable microcontrollers turned up the Adafruit Trinket (http://www.adafruit.com/product/1501). Do you suppose that would do the trick? Do you know how I can find out what kind of signal the controller has to send to simulate a shutter half-press?

I'm getting the video out through an HDMI cable with a right-angle connector going into the camera, and a bulkhead and 66-foot HDMI cable made by diveandsee.

That's an impressive little beast, especially at that price.

I had a quick Google and you just need to pulse the focus pin to GND (I'd expect 100ms would be a good). I'd suggest using a digital in, transistor out optocoupler between the microcontroller and the camera. That would be the minimum number of components to wire up while being pretty much bullet-proof in terms of camera safety.

It looks like Nikon use a variety of proprietary connectors so I'd buy a cheap shutter cable release to match the camera and then cut the cable off to get the connector and cable.

Steve.

I had a quick Google and you just need to pulse the focus pin to GND (I'd expect 100ms would be a good). I'd suggest using a digital in, transistor out optocoupler between the microcontroller and the camera.

Thanks, Steve. I just got all the parts to try this and it works great.

Just an update on this for anyone who reads it with a similar question in the future. Steve's idea to use a microcontroller to simulate a "shutton button half pressed" (i.e. focus) signal every 29 minutes worked great to trick the 30-minute auto off timer. And the camera (Nikon D5300) had no overheating or other problems running a nonstop HDMI feed to the Atomos Ninja Blade for 3+ days.

However, the battery powering my microcontroller died... and the thing still worked!! I still haven't figured out how, but I must have short-circuited it somehow with my amateur soldering or something else. It turns out that (at least with the camera in manual focus) one can just continuously send that focus signal (i.e. hook the green wire to the black wire within the remote shutter cable and leave it connected) and that keeps the live view running. It doesn't need to happen at regular intervals, so no microcontroller is required.

I was a little bit concerned about eating up too much of the camera's battery this way, since I'm trying to squeeze every bit of life I can out of my power supply. A multimeter showed the connection using 0.5 to 0.9 mA current. I found that I could put a 1 kilo-Ohm resistor in line between the wires and it still kept the camera alive, but it didn't work with a 1 mega-Ohm resistor. So I'm using the 1k, which makes the power draw basically negligible.

Now my final setup is just the black wire connected to the green wire via a 1k resistor, with things appropriately insulated from each other and protected under heat shrink tubing. So simple. At least the microcontroller thing was fun to learn about.