To move your solar panel or panels I would suggest using a linear actuator with position feedback rather than an old wiper motor.
The wiper motor will be under powered and too fast and has no feedback to let you position it and the mechanical part would be a nightmare.
There was a discussion in the past few days here about positioning a solar array using know time and location, using 'Solar Path Algorithm' or SPA.
You really don't have to get that fancy. A simple motor, geared down enough, and a single axis tracker is about all you need, once you know the proper average angle needed for your latitude. Even if you need dual-axis positioning, just being able to set the angle once a month or less to account for winter/summer variation will likely get you within 2-3 percent of maximum efficiency.
Once you have that, your feedback system becomes the measurement of voltage output of the panels. Since for the most part, the panels will only move along the single axis in the same direction all day (except when the sun sets, then you move them back to the beginning, for the next day), just move them in that direction until you have maximum voltage output from the panel, then stop the motor. When the voltage falls below a certain absolute minimum (say below 1-2 volts?) move them back to the beginning, because it is likely evening.
You could do this with a microcontroller; you could also do it with simple circuitry (which would probably be more robust). In fact, you could do it with a solar-heated system if you were so inclined (kinda like a hydraulic system where the expansion of water from the sun's heat drives the system - at least, I've seen an experimental tracker design that supposedly does this).
I'm not sure why people like to over-complicate solar panel tracking systems, but they do (now, if we're talking something using mirrors for focusing or such for large scale power generation, that's a different story; even there, though, many systems have designs that have single-axis tracking or none at all - it's just more efficient, and less prone to breakdowns).