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.
![Raspberry Pi with Pi camera](http://scubapi.net/wp-content/uploads/2016/03/DSC_0053-1-1024x681.jpg)
Raspberry Pi with Pi camera
For the housing, I opted for an old dive light.
Remove the reflector and insert Raspberry Pi.
![Raspberry Pi in underwater dive light](http://scubapi.net/wp-content/uploads/2016/03/DSC_0051-1024x681.jpg)
Raspberry Pi in underwater dive light
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.
![Testing & adjustment of DC-DC converter](http://scubapi.net/wp-content/uploads/2016/03/DSC_0062-1024x681.jpg)
Testing & adjustment of DC-DC converter
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.
![DC-DC converter output voltage before adjustment.](http://scubapi.net/wp-content/uploads/2016/03/DSC_0063-300x199.jpg)
DC-DC converter output voltage before adjustment.
![Voltage set for 5.16vdc for powering the Raspberry Pi](http://scubapi.net/wp-content/uploads/2016/03/DSC_0064-300x199.jpg)
Voltage set for 5.16vdc for powering the Raspberry Pi
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.
![Assembled ScubaPi #2](http://scubapi.net/wp-content/uploads/2016/03/DSC_0067-1024x681.jpg)
Assembled Scuba Pi 2 in dive light housing.
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!
![First selfie with the ScubaPi 2 underwater camera.](http://scubapi.net/wp-content/uploads/2016/03/scubapi2-selfie-300x225.jpg)
First selfie with the ScubaPi 2 underwater camera.
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.