Or I could actually have an open circulatory system. The interstitial fluid could be mainly water with salts dissolved in it to increase the conductivity. This would help maintain a more stable body temperature, but oxidization of the contacts that would line the water-sac's walls would be a serious problem. I could try and find a different conductive liquid, or use a conductive metal that resists oxidization for the contacts. Tin-coated copper wire seemed ideal for this. I'd probably also want something to actually, y'know, circulate the water.
The integumentary system was next. The skin would need to be a porous material, to allow the robot to sweat & thus regulate its temperature. There are plenty of manufacturing processes that produce porous latex, which would be ideal for "skin," but latex deteriorates over time so that pretty much ruled out latex. And though rubber is generally considered to be waterproof, it seemed there were some methods of making rubber porous, so I might be able to use that. But I wasn't finding much here, so I decided to leave that decision for later & ask around about what I might be able to use.
Optimally, I would be able to find a material that was both porous, but also one with pores that could be opened and closed via some mechanism. Failing that (which I probably would) I would need to craft centrally-located sweat glands that released water from the circulatory system, and then provide a means for the liquid to disperse underneath the skin. And underneath (or embedded in) the skin would need to be an elaborate system of sensors â€“ touch and temperature.
So if I was going this route, the "digestive" system would in fact need to be extended. In addition to energy (certainly batteries, preferably rechargeable), the robot would also need to take in water. Still, though, it would be pretty simple. The battery issue would be something I'd have to return to later down the road, when I would have an idea of the robot's normal power consumption levels. That could be tricky.
Since I was on the subject of fluids, I figured I'd move on to the urinary system. It would be useful in getting rid of excess water when sweating wasn't desired, but also to clear the system of excess minerals from whatever. Trace minerals in the water it drank, or anything else that might, somehow, get into the system.
If necessary, I decided I could break the fluid-sac "circulatory system" into separate compartments and adjust the concentration of water and salts throughout the body with a series of valves that I suppose wouldn't be too dissimilar to the lymphatic system. But that was stretching it, and I couldn't yet see any use for that.
The next important system was the respiratory system. Not because my organism needed to breath, per se, but because it would need to talk. (11/07/06) Much like human lungs, the lungs of my creation would function like bellows, using muscles to expand them & thus draw in air from the outside, then expel air naturally while at rest. Since oxygen would not be necessary for biological functions, I could safely use simple air sacs instead of a spongy material like mammalian lungs. I sketched out structures corresponding to the wind pipe, the larynx and glottis (the space between the vocal cords), the epiglottis (the part that covers the wind pipe during swallowing) and all the other parts. The nose was also a really important part of this system, both for its function in the sense of smell and for the part it plays in speech.
I needed to start thinking about how to control these systems, so I got to work on designing the nervous system. I started with the autonomous NS because it was more important to have the creature's base systems working and "alive" before I worried about central processing and consciousness.
The ENS (enteric) was first, since it was for the most part independent of the rest. It would be in charge of monitoring the system that would draw energy from the batter & maintain the proper level of charge in the circulatory system. For the most part, it would be possible to grossly simplify this part of the nervous system in relation to a biological human's.
The next two, the sympathetic and parasympathetic NSs, would be far more complex. They would control control the two base automatic states of the robot: active or danger, and rest or relaxed. But what would trigger these states? Regardless of the answer to that question, I could still continue on & make diagrams of these closely tied networks. I knew what they would control; the question remaining was what the inputs would be.
The somatic NS's design, on the other hand, was fairly straightforward, albeit quite extensive. Its base is in the central nervous system, specifically the precentral gyrus or primary motor cortex of the brain (I couldn't tell if they were the same thing or one was part of the other, but it didn't really matter as long as I understood what was going on in a general way). That root connects to every single skeletal muscle in the body. In addition, the somatic NS includes all the nerves that connect the sensory organs to the CNS.
And in-between all these afferent (sensory) neurons and efferent (motor) neurons, a network of interneurons (relay or association neurons) connecting the two. All the neurons in the central nervous system would be of this type.
And so the central nervous system. The spinal cord is more or less the "trunk" of the nervous system, the main pathway that information travels on between the brain and the peripheral nervous system. It is encased by and protected by the spine. The very large number of wires I would need both entering and exiting the spinal column would prove quite tricky. In theory I wouldn't need to encase this in the spine itself, but for the meantime I would use that model. Best not to second-guess evolution. Damage to any part of the neurons that constitute the spinal column is very debilitating, and would probably be far more common if it wasn't protected thusly.
To reduce the number of wires I would need, I decided that I could probably encode the information sent across the spinal column and place a small chip inside each vertebra that I would program to parse the data, encoding the signals from the sensory nerves and decoding the signals from the brain.
Exhausted, it was time to take a break. I'd been doing nothing but designing and researching for several days, now. I needed to rest and gather my strength before I tackled the brain. Even so, I figured I was on a roll so I started looking around for materials. I might change my mind on certain things still, but I could always use what I acquired for something else down the road.
The metal for the skeleton was the first thing I bought. It took the form of a couple old bike frames. I knew I could use the smithy down the street from where I lived to melt them down & fashion what I needed. Then I went to the electronics / hobby store where I got most of my components, and went on a shopping spree. I picked up anything I thought I might need, and then some. I asked around and even found a place that could manufacture the rubber balloons lined with diodes I was planning on using for the circulatory system. No luck on the skin, though. Still unsure of what I was going to use as a power source, I bought a couple types of batteries I could use for testing purposes.
I stopped by the smithy on my way home from the electronics store to see if anyone was still there (it was getting late), and let the owner know that I'd be wanting to use the facilities in the near future. The owner, Cassius, was a cheery fellow, with a small frame and long bushy beard. He looked more like an ancient philosopher than a blacksmith. But I'd seen his work and there was no questioning his skill. He knew me pretty well, and was always kind and helpful. And I was in luck; I caught him as he was finishing up for the night doing paperwork.
"Well hello, Cadmilus. Here's a face I haven't seen in a while. What can I do for you this evening?"
I bowed slightly as I entered the room, and replied, "I'd like to use the forge again. I have a new project I'm working on."
"Come, come. Please sit. It's been a long time. Or do you have to get going?"
"No, it's alright," I said, and took a seat opposite his desk.
"So tell me, what are you working on, now?"
"I'm designing a robot. Humanoid, so I guess that'd make it an android."
Cassius leaned back and laughed. "Oh ho, so taking after the father of your namesake, I see?"
"Of course. Cadmilus was the son of Hephaestos, who built a man out of bronze."
"Hah. I know the story, but I never knew He had any children."
"So when will you be starting?"
"It's still pretty early. I haven't started building anything yet. I was just passing by, so I figured I'd stop in. So I probably won't need anything for a while, yet."
"Well it's always good to see you. It's been pretty quiet here the last couple months. You still have a key, right? So you're free to start whenever you wish. No one's working on anything big, so you won't be getting in anybody's way."
"Alright, thanks. It'll probably be sometime next week, but I might want to stop by a little earlier to try some things out. I should let you get back to your work, though. I'll be seeing you soon."
So I went home, and again I dreamed. This time I found myself in a mechanical menagerie. I'd heard of places like these; ancient kings had them built to showcase their wealth. Tin tree-trunks with oxidized copper leaves to lend them a greenish color, and clockwork birds chirping and whirring on their branches. Delicately wrought golden flowers complete with bees, buzzing in perpetuity. Every species of flora imaginable, populated with automatons that gave the illusion of life, but felt... dead.
I walked through the garden, marveling at its beauty and craftsmanship, but I was filled with an immense sadness. As I walked by a brass and aluminum doe, it turned its head to and fro and pretended to nibble at the grass in front of it, but it did not respond at all to my presence. It was never programmed for that. It wasn't programmed at all, in fact. It was purely mechanical. It had no information-processing facilities, no soul. It couldn't react to the world around it.
All these animals were wind-up, though, which led me to wonder who had set them in motion. Before I had even finished asking myself the question, I knew who it must be. Sure enough, walking several meters ahead of me I saw the same robot from my previous dream.
7517 words and counting something like 1709 or 1435 words for the day, depending on how you're counting