Also, I'm not sure where the power supply went. There's not a dedicated port for power. We probably used a usb battery back, and went through the FTDI programmer on the microcontroller. Generally speaking, that's not so great to do, supply wise, which would also explain the capacitor there on the back right side.
The neat part, however, is at the front. The idea was to make a sensor that could be used for obstacle detection which was cheap, and had a fairly wide profile. What we ended up doing was making whiskers, which isn't novel at all, but what really made these guys shine was the very careful way we designed them. Take a look:
Originally, the three pins of each header had the whisker threaded through it in a convoluted pattern, to provide spring tension. I figured out later that passing it through only once, but with some curves like those shown above, works a lot better. In particular, the distance through which the part which makes contact is reduced, which makes it much more rare that the flexing when bumping an obstacle bends the wire out of form, which was a huge pain in the ass with the first design.
The other thing that's nice about this layout is that you can cross the antennae over one another. When the angle at which they intersect is fairly acute, this creates an overlap in the sensor profile, eliminating the blind spot that often appears between two sensors performing the same function. That means it can find things like table legs much more easily than most other whisker based obstacle avoiding schemes, which is neat.
I'm looking forward to getting the board back on a chassis, so I can take some video.