After learning a few things from the first attempt at ScubaPi, I opted for a simpler approach. Instead of adding the display and 10-DOF, I went for just the camera. This meant a smaller housing and fewer things to work with.
For the housing, I opted for an old dive light.
Remove the reflector and insert Raspberry Pi.
Now, the housing isn’t big enough for a conventional USB batter pack, nor does the usb power cable fit when plugged into the side of the Pi. The solution is getting a dc-dc converter and powering it off of a pair of 9 volt batteries. The DC-DC converter is fairly inexpensive; I found mine on eBay.
This DC-DC converter is adjustable, so I had to adjust it down to provide a steady voltage close to 5V. I opted for a bit higher, since the voltage would drop once the Pi was attached.
Now, to package it up, I used some polyethylene packing foam to keep things in place. Also, the back of the camera was insulated with electrical tape and affixed to the front of the ethernet connector.
I also covered the camera’s LED with a bit of tape, since I thought the light might reflect off of the inside of the dive light and mess up the photos.
Here’s the first in-water test:
One interesting thing I’d not thought about was buoyancy. The dive light was originally designed to have four D-cell batteries in it. With the Raspberry Pi, Pi Camera and power, it wasn’t nearly as dense. The ScubaPi2 required a good amount of force to keep it down. Now, what do you do with a new camera? Take a selfie!
The color balance was a bit off, but it still worked.
Since I had no external controls, I wrote a couple of scripts to start a time-lapse series. There is an init script that starts at boot and it calls the script that takes photos every 5 seconds (5000 milliseconds). You can see the scripts in my github repository that I created for ScubaPi3
Now, I wanted to go back to my original idea–Raspberry Pi with display and inertial measurement unit (IMU). Luckily, my Sense Hat arrived and the Scuba Pi 3 was started.