What I want to do
I want to examine potential low-cost, underwater imaging techniques by adapting approaches originally developed for aerial mapping. Especially regarding new possibilities opened up by the Mobius Actioncam,
In the process of selecting materials for a waterproof KAP rig, I came across some of those cheap floating LED "disco balls" like the one pictured below-
Of course, its impossible for me to see something like this without trying to figure out how I can hack it to do something else... Seeing as I don't own a pool, it would be of little use in its intended purpose, but I DO live on the coast and I WAS looking for something that could both protect a kite camera from crashing while also protecting it from water damage should it fall into the ocean...
Ultimately, the shape of the LED disco ball didn't lend itself to easy harnessing on a kite line, but it DID open up the possibility for exploring a whole new world- underwater!!! Considering our overarching project goal is to find better ways of tracking a species of non-native crab, an underwater capability seems especially fitting.
In its stock form the LED Float looks like this-
The LEDs and Battery are housed in the lid while a heavy circular weight is embedded in a plastic tube that sticks out of the bottom.
If the yellow weight is removed (carefully without breaking the plastic) it leaves a perfect space to fit a camera lens.
.The key enabler for this project was the ability to add an extension cable to the lens module on the Mobius Cam. In this case I used a standard lens though a wide angle might work as well.
I took some extra waterproofing measures by adding silicon sealant around the edges and by wrapping the main camera electronics with a dry bag. After adding some heavy bolts for ballast and foam pellets for cushioning, the end result looked like this-
The top lid has a little hole through which a line can be attached.
The only thing left to do was to awkwardly throw it in the water!
While some moisture did leak in, it wasn't enough to affect the camera and further investigation revealed a loose corner of the dry bag had been caught in the threads of the lid and created a small gap.
The camera results were far better than anything I had imagined! I set it to video mode for the first time but I will try using timelapse too. Some photos are blurry but I can't tell if it has to do with the transparent plastic on the float or if its just a simple focus issue.-
The full video feed and selected screen stills can be found at https://picasaweb.google.com/107186102357963872918/UnderwaterMobiusCam1stTest?authuser=0&feat=directlink
Questions and next steps
The implications of this successful experiment are potentially huge! So many grassroots mapping projects are already focused on coastal regions or marshlands and such techniques would allow them to use some of the same equipment to view and collect data underwater! The initial premise can be improved on in immeasurable ways. The most obvious for me would be to test how the Infragram Point and Shoot version of the Mobius Cam performs underwater! It could also be adapted as a great platform for other PLOTS projects like the RIFFLE by adding Arduino sensors or even a Raspberry Pi. Another immediate possibility is the fact that the stock LEDs that come with the floating light show can easily be swapped out for IR or smarter RGB LEDS like the Neopixel for various nighttime experiments. However, I would want to confirm that such experiments would not have a destructive impact on wildlife first. I know some fishermen use IR cams as fishfinders so it must be possible, but its not something I would do without significant input from others. In theory, I suppose one could even develop the float for my original intended purpose as a hybrid KAP/Underwater rig and actually crash the kite into the water on purpose! That leaves serious practical issues like reeling in a wet kite of course, but it would be a good way to make a deep cast... Immediate improvements I will be making will be improvements to the ballasting system to make the bottom more stable, further waterproofing measures and I might even try using a fishing pole to cast the float farther than I can physically throw.
Why I'm interested
Part of a long term effort to develop citizen-centric research techniques to track impact of an invasive crab species in coastal Maine- http://publiclab.org/notes/code4maine/05-08-2014/mobilizing-data-to-combat-the-evil-green-crab
Began as a standard aerial mapping project using KAP techniques- http://publiclab.org/notes/code4maine/06-25-2014/kap-test-for-invasives-monitoring-project
Developed further into a design/build process for incorporating the new Mobius Actioncam into a water-resistant Kite Aerial Photography rig- http://publiclab.org/notes/code4maine/07-09-2014/kap-rig-for-mobius-action-cam
Version 2= Photo Fishing!
In both attempts to create a waterproof housing for the Mobius Cam, the most challenging part was accommodating the lens. In the initial underwater design, I was able to use the bottom of the clear plastic stem beneath the floating light platform to fit the Mobius lens. However, as some commenters pointed out, the transparent plastic of the LED rig really wasn't meant to be an optical lens, and it didn't take long for it to get so scratched up it wouldn't work. So back to the design board! So if my first design began life as a Kite rig, then my new design, rendered below, bears more of a resemblance to the sport of fishing... Only we're fishing for photos in this case...
The idea is to use the floats as one would use a bobber on a fishing line, whereas the camera could be attached akin to a "hook"to sink below at varying depths.
As of this writing, I was able to find at least one U.S.-based retailer of specially designed underwater cases for the Mobiuscam- http://www.eyeofmineactioncameras.com/Mobius_Actioncam_Waterproof_Housing_p/emuwo.htm. The $30 price tag is more than reasonable considering the range of alternatives. That would leave plenty of room in the floating rig to add sensors, transmitters etc... Pictured below with a GPS antenna.
Questions and next steps
As of this writing, the new design should be ready for testing within the next week as I'm still waiting for the new camera case to be delivered. In the meantime, I've been experimenting with different sensor combos to embed in the float. Many questions remain concerning the overall usefullness of underwater photography. Does it complement grassroots mapping? If so, how should the imagery best be utilized? Could underwater views be added as a layer on Mapknitter? If so, how should they be georeferenced? The photo below shows one of many GPS configurations I've been experimenting with-
The photo shows a solar powered LED Light Float with factory electronics removed and replaced by various components designed for wearable applications. All of my experiments are based around adafruit's excellent Ultimate GPS Module which includes an RTC, built-in datalogging and an antenna attachment.
Many RC/UAV pilots have reported significant interference when using the Mobius ActionCam with a GPS. However, such issues would be highly unlikely if the camera was submerged while the GPS was isolated in its own enclosure on the surface.