The evolution of my 3D rig continues with v1.3, which came about because of the issues I had with the previous versions:
v1.0: Too bulky, can only do landscape 3D pictures.
v1.1: Compact but cramped shutter control box, but reliable. Can only do landscape 3D pictures.
v2.0: Used only AA batteries for the shutter control box and cameras. Heavy (7 AA batteries were needed), and can only do landscape 3D pictures.
Last year, I was trying to resolve the landscape-only issue and cramped shutter control box with v1.2. I had some success with taking pictures, in both landscape and portrait mode, but the wiring for the mini shutter control box broke pretty easily.
1) After making v1.2, I ended up with three cameras of the same model type, so I didn't need to make some kind of structure to switch from landscape to portrait mode.
2) USB hubs need to provide the same voltage to all the stuff plugged into it, so I really didn't need to solder USB ports in parallel when I already could find a cheap USB port and connect batteries to the power input.
3) Each camera (the PowerShot SD400 model, other models may require higher voltage) only needed 1.5V to activate the shutter. I didn't really need an AA battery when for a momentary switch, a button battery would do.
4) There are a lot of ways of holding a button battery from using clothespins to using binder clips to folding cardstock
With these revelations, I just needed to replace one of the capscrews that held one of my cameras with a socket cap screw so I can add another camera. Two of the cameras will have the left camera StereoMaker SDM software installed while one camera will have the right camera software installed. I will rotate the rig about the right camera to switch from landscape to portrait mode.
With the USB port I found for less than $5 (one that came with mood lighting), a removed the mood light LED and placed the switch and battery in its place.
An alternative is to build some form of battery with USB plug and momentary switch and plug it into the port where the power input goes, thereby avoiding the need to hack the USB port itself.
My backup kit has the same hex key set and wrench, but I added a few things, such as an extra socket cap screw and a bolt I can use in case I only want two cameras.
To fit the battery in the USB hub, I had to remove the prongs on the binder clip, but I will need them if I need to replace the battery.
I definitely still need to field test this rig...