S.A.M. (Short for "Sentient, Autonomous Mechanism" or "Smart Ass Machine", depending on his (and my) mood on a given day) was one of my first real robot projects, started in 1978 when I was around 15.  His "brain" was a single-board Z-80 computer (the big square object in the middle of his "back" in this picture), with many bits of TTL I/O, a couple of serial ports, a bunch of counter-timers, and several D/A & A/D channels.  The base was taken from the book "How to Build a Computer Controlled Robot" by Todd Loofbourrow - I had built the robot in the book, and had used my KIM-1 to control it.  Later, I decided that just a little platform was kind of boring, so I added the upper torso shown here.  The torso (mounted on a "lazy-susan" turntable bearing) is rotated by a heavy-duty gear motor driving a chain and sprocket assembly from a bicycle.  The base is powered by two of the (apparently no longer available, which is sad) all-metal rubber-tired "motorized wheel" assemblies that Herbach & Rademan used to sell, with a large rubber-tired caster in front.  The head platform (mounted on a small "lazy-susan" bearing) was originally rotated by a surplus gearbox from a Mattel "Big Trak" with some rubber-tired wheels mounted on the output shafts.  This arrangement was later replaced by a small gear-head motor driving a large gear mounted to the center of the turntable.  The device in the head with the tubes sticking out the front is a directional light tracking device.  Each tube has a CDS photocell at the bottom, and is painted flat black inside.  A comparator circuit tells the computer which direction the brightest light is coming from.  This device could also tilt up and down with a small gear-head motor, to track light sources vertically.  Most of the circuitry was installed on small plug-boards from Radio Shack, mounted in a card rack below the CPU card.  This rack could be tipped back 90 degrees to facilitate easier access for testing.  In addition to motor driver circuits, there was a "Sweet Talker" speech synthesizer board so he could talk.  Power came from a large "gel-cell" marine battery (for powering trolling motors on boats), which was slung near the ground in the center of the base.  Two 6V lantern batteries (later replaced by a 12V motorcycle battery) provided separate power for the electronics.   All motors were isolated from the electronics via relays and/or opto-isolators.   After these pictures were taken, a set of metal panels was installed on the "facets" of the base, with lever switches behind them for collision sensing.   A Polaroid sonar range-finder was also added later.  If you check out the other photos of S.A.M., you will notice an "arm" sticking out the front.   This was a prototype made from an old swing-arm desk lamp and some "fingers" from a robot hand design using brass tubing, bicycle chain, and 1/16" steel cable to allow natural bending of each finger.  It was later replaced with a much heavier duty aluminum framework arm operated by two 12VDC "linear actuators".