I have mentioned previously that all my robots are named Herbert. It would only make sense that I would have a sound logical reason for this choice of name, but of course I do not. Truth be told, the name comes from the song Starface by White Zombie, which actually comes from an episode of Star Trek.
In order to keep each Herbert separate (in my mixed up mind at least), I attach a number to the end; thus Herbert 1, Herbert 2, and so on. I figure I should keep this same naming convention for the Evolution Project, but would like to avoid any overlap between robots I build "just because" and those designed as a part of the project. To that end I have opted to use the moniker of 1701 for all evolution project robotics, or rather artificial life forms. And yes, 1701 is the number of the Enterprise in Star Trek. It seems my geekiness knows no bounds.
The project begins in the realm of solar power. Evolutionary it makes sense; energy for life must come from some place and without another life to tap into (consume) there is no other available source of sustainable energy. For robotics this means solar cells. The second part of this is the consuming of said energy to perform some arbitrary task or another, even if it is just to regulate the energy. These two parts could be met by attaching a resistor to a solar cell and calling it a day. This is not enough for the project, as the goal is artificial life and therefore will need something more to meet those requirements. That something more comes in the form of a solar engine.
There are a variety of solar engines that can be created, many of which are outlined on the BEAM Wiki and at Solarbotics.net. Each engine has different strengths and weaknesses, as well as different levels of complexity. For now, simpler is better; provided the core requirements for artificial life are met. One of those requirements is Organization and logic circuits. For this I have chosen the "Miller" solar engine. The design and function of a Miller solar engine are described very well in the above websites, so I will spare you the details and only cover the application and changes I have made.
The base Miller solar engine provides a logic circuit to our little life form. When voltage reaches a certain point from the solar cell, the circuit turns itself on and expends the energy across some load. For the sake of simplicity that load can be a resistor, but then it would be quite boring and we would never be able to witness the metabolism or response to stimuli (in this case the stimuli is light energy). Instead we will use an LED as the load and to fall in line with what would really be the simplest artificial plant life possible, it will be a green LED.
The only other change that is made to the base Miller solar engine is the removal of the second capacitor (usually labeled C1 in schematics). The second capacitor allows the voltage trigger mechanism (in most cases a 1381 IC) to remain "on" past its normal shutoff point. This provides power to the load for longer periods of time, which is helpful for heavier loads such as a motor. For a simple diode it is not needed, and the removal gives us a little more of a living effect. Thus we have a completed schematic for the first artificial life form in the evolution project, Herbert 1701 Species A Generation 1.
For all cases throughout this project I will create a circuit design and corresponding schematic. Where it is possible, this schematic will be put together on a solderless breadboard to test and tweak the design, as well as show proof of concept. Some generations I will build out the completed circuit to create the actual artificial life form, but others I will not. It will really depend on the differences between generations and species, the cost and availability of parts, and the level of circuit completion required to test the life form's function.
In this instance I performed all three. It is after all the first of the Herbert 1701 series and should be available for generations to come to look back upon and say, "This is where we came from." Alright, maybe not for that last part. In the case of Herbert 1701A Gen 1 I went the freeforming (creating a circuit without breadboard) route, as it provides a smaller footprint. The soldering is a little trickier, but it creates a nice compact circuit that, despite its simplicity, manages to look pretty cool. So without further adieu, I present the first of the Evolution Project artificial life forms: Herbert.