I set up the breadboard prototype shown in the first project log with the solar cell pointed out of my apartment window. It is receiving sunlight at a very poor angle, through a window, and likely cannot ever receive direct sunlight due to trees on the street and nearby high buildings. Nonetheless, during parts of the day, non-zero power was recorded, seen below. Curiously, occasionally the power drops to zero, especially on the second day. Some storms came through June 12th, so probably the sun was occluded enough that no measurable power was seen.

The solar cell produces nonzero voltage even in very low light, so the voltage plot below provides a better idea of sunrise and sunset. It also is more constant, even if clouds come through.