When last we left our hero he was trapped behind the age old conundrum: "Which came first, the chicken or the egg?" Mere seconds from impending doom our hero deftly cracked open the egg into the flour and used the concoction to batter-dip the chicken, resulting in the beautifully prepared fried chicken that now rests upon the serving platter. We rejoin our hero as he sits down to enjoy a well earned feast.
Enough of that goofiness. The real question here is: Which came first, the movement or the senses?
Up to this point in the Evolution Project
our artificial life forms have been very simple creatures capable of little more than gathering energy, knowing when enough has gathered and expending said energy. Actually nothing "little more" about it; that is all they have done. I think it is time for evolution to change all that.
Movement would be a phenomenal thing at this point. Movement would provide some action to observe and make the ALs more "lifelike". Obviously, movement needs to come first. And with movement, the little Herberts could go forth and wander the world as the free spirits they were intended to be. Until they wandered into a shadow that is; and eventually they all would. Then for all intensive purposes the little Herberts would slip into comas never to be heard from again.
Evolutionarily, movement on its own is a bad thing. Movement expends lots of energy. Movement brings life forms to danger not otherwise present. Movement also brings a life form to an energy source or allows it to flee from danger. The difference between good and bad is the addition of senses.
Senses tell a life form something about its environment. They provide information. While senses, or sensors as the case may be, on their own can gather information, without a means to act on that information the sensors are useless. But they are not harmful. They may expend a bit of extra energy or none at all or even generate energy on their own. Either way it is inconsequential compared to the energy used from movement, especially movement without purpose; and far less dangerous. "Which came first" are the senses. Any other way and the species would have died off.
The next logical step, or maybe illogical step, for Herbert would be the development of some type of sensor to better understand the world around it. Being that Herbert is a phototroph of sorts it would stand to reason that part of its physiology would become more sensitive to light patterns as the species evolved, eventually becoming something akin to a light sensor.
Herbert 1701 Species B Generation 4 introduces this concept in its design with the addition of photoresistors (or photoconductors or CdS cells). CdS cells change the resistive quality based upon the amount of light that falls on the cell. As the resistance changes (decreases for more light, increases for less light), the amount of current that reaches the base of each 2N2222 transistor changes, which in turn changes the amount of energy that passes through each transistor and the ajoined LED.
One of the problems with CdS cells is they are notorious for inconsistencies from one cell to the next. To combat this problem, our Herbert generates an adaptation seen already in the Herbert 1701 A Species with the addition of a balancing mechanism (obviously that gene was passed on). This allows a more equal distribution of energy flow across both LEDs than through the CdS cells themselves.
There is one further problem that the addition of the CdS cells creates. Herbert is a phototroph, meaning it generates its energy from light (the actual definition includes conversion of CO2 and water, but for this phototroph
will do). The solar cell that Herbert uses, like the majority of solar cells out there, are more sensitive to the near infrared spectrum of light. The further away from the 850nm mark, the less energy the solar cell generates.
Why is this important? The CdS cells that Herbert 1701B Gens 4 & 5 have are most sensitive to the visible light spectrums, somewhere around 520nm. So while they can detect light, it is not the most efficient detection of light; and in some cases completely useless detection. Herbert 1701 Species B Generation 6 solves this problem by adapting the light sensors once again to something more specific to its needs: photodiodes.
Replacing the CdS cells with photodiodes provides a few advantages to Herbert 1701B Gen 6 over previous generations. The first is the more focused light detection found in the photodiode, in this case around the 850nm spectrum. Second, photodiodes generally react faster to changes in light levels than do CdS cells. This means Herbert 1701B Gen 6 is quicker on its feet, umm, board than Gens 4 & 5. The third is that photodiodes, which are placed in a circuit reversed in polarity from a normal diode, not only provide the needed sensitivity to light, but they also generate a small amount of energy. In a creature that needs to be as power conscious as possible, this is a big plus.
As the amount of light passed over each sensor varies, so too does the amount of current that can flow through the paired trademark green LED that Herbert uses to expend energy. In the plant world, this would be the equivalent of a leaf turning bright green in the sun and brown in the dark. Except in Herbert's case, the leaf does not fall off and die, merely waits to reenter the sunlight.
Oh. Almost forgot. It was the egg