I hooked everything up outside to do a run with actual bubbles. The first issue I ran into was the Opera Mini browser on my phone wasn't playing nice with my web interface for some reason. Switched to Chrome, everything solved or so I thought.

I then added bubble solution to the machine and tried it, not a single bubble. Turns out that the fan wasn't running fast enough to create the bubbles. Measured the voltage of my battery pack at its terminals: a little bit over 5v (using 4 AA nimh cells). Measured the voltage at the terminals of the bubble machine: around 2.3V! Yup, quite a nasty voltage drop from a combination from the wires and the L293D. I plugged in my batteries directly into the machine: a shower a bubbles.

Solution: ditch the L293D and use beefier wires, using breadboard wires on the bubble machine side doesn't cut it.