The strong survive. That is one of those statements thrown around when talking about evolution or natural selection. It is also one of those statements that people opposed to the idea of evolution warp to mean something other than what was intended. Sort of like a woman slapping a man for shouting out "bare run" as he passes her during a jog through the woods. An ultra-feminist takes the verbal words to mean "nude run", where-as a non-biased person would have understood that the man was shouting a warning about a "bear" and that the woman should "run" as a result. It is why scientists rarely use the phrase "the strong survive" any longer.
Natural selection is a much better term that means the same exact thing. An animal of the same species with one genetic trait is more likely to survive than one with a different genetic trait. Which one survives depends entirely on the environment and the other animals around (including ones from the same species). Take for example two moths; one moth is dark brown, the other light brown. Which moth survives? If the two moths are in a forested area where the tree bark is a dark brown, the first moth is more likely to survive. It does not mean the second moth will die out, just that it is less inclined to survive in its given habitat. If the environment has no predators for the moths, then both moths are equally likely to survive.
Herbert 1701 Species C Generation 5 is an example on this concept. By changing the trigger voltage to a higher value (around 5.6V) we produce a simple adaptation over Generation 4. Up until this point there have been pretty clear reasons behind changes in each generation or species of Herbert. More efficient use of energy, the inclusion of sensors, and the ability to move all have simple logical advantages when implemented correctly (and we covered "correctly" for each as needed). The change in Species C Gen 5 does not provide a definitive advantage over the previous generation, nor is it a definitive disadvantage.
I previously discussed how additional voltage can produce an advantage by offering more power to the motors for stall situations. The disadvantage is that it will generally take longer to reach the trigger point for that higher voltage, and under low light levels that trigger point may never get reached. So which is the winner, a higher or lower voltage trigger point? That is what is unclear.
Were I a gambling man, my money would be on some sort of balance between voltage levels. Even better would be a variable trigger voltage based on the amount of light that Herbert was currently basking in. Herbert 1701 Species C Generation 6 is the embodiment of this concept. Using an IR LED in a reverse bias configuration produces a max8212 solar engine that varies the trigger voltage based on the amount of IR light available. The configuration shown in this schematic produces a trigger level that varies between approximately 2.68V in low light conditions and around 5.7V in direct Florida sun. It is this variable solar engine that is at the heart of Species C Gen 6.
It might seem as if the variable trigger level would provide an advantage over generations 4 and 5, but like the moths, the advantage depends entirely on the environment. The most efficient method of determining advantages or disadvantages for each adaptation would be through nature's very own Natural Selection process. And that is exactly what I intend to do with each of these three generations. The winner of this selection process will be the generation that I will continue to evolve forward, the others will be shelved (temporarily at least).
Not wanting to bias the selection process in anyway, I will not be determining the environment. Instead, the robotics community has already decided upon the environment that they feel provides the best test of a solar robot's (phototropic artificial robotic lifeform's) ability to survive: The Photovore Competition. The competition rules I have opted to use are the BEAM Photovore rules straight from Robogames. Two Herberts enter, one Herbert leaves.
If only I had an audio track of Tina Turner saying that last bit.