While the DarkStar dual axis controller features convenient editing of tracking parameters via the DarkBlue Android application, our TinyTracker and Track'n Park controllers also utilize the same advanced tracking parameters (which can be customized with an AVR programmer device). The most important values are the Daylight and Sunlight threshold values which determine when the controller is active and when tracking events actually happen. To help explain these settings we've created this diagram to show how these values are used.
Both the Daylight and Sunlight threshold values are calculated based on the sum of the east and west sensor values (or north/south for elevation control). With the Dark Star controller these values are conveniently displayed next to the actuator position bars near the top of the display. To tune your controller simply add the two numbers (###/###) together, and based on the current conditions (cloudy, sunny, twilight/night) set your parameters accordingly.
The Daylight threshold is responsible for determining when the controller "wakes up" in the morning. The TinyTracker series doesn't incorporate pulse feedback like the Dark Star and Track'n Park controllers, so it doesn't have a night time park position. Instead it performs the east-return after sunset (when used for elevation axis it will return to a horizontal panel position). The Dark Star and Track'n Park go to their user configured park position after sunset and then perform the east-return function once the light level reaches the Daylight threshold in the morning.
The Sunlight threshold helps prevent the controller from unnecessary tracking events (commonly known and "seeking") that can occur under cloudy or partly cloudy conditions. Tracking events only happen when the combined sensor values exceed the Sunlight threshold. This not only eliminates seeking behavior, but also minimizes motor wear since current surges from repeated motor start ups are a common source of armature/brush failure for DC motors, particularly common low cost/DIY motors that were not designed for solar tracking applications.