More pictures.  All thumbnails, click to enlarge

Shows Snuffy's top deck which has the UVtron on the left,  the Eltek pyrosensor in the black/blue can in the center (mounted on a servo), the starting tone detector in the black box on the right, the motor and propellor in the front, and a green header PC board which just helped to minimize the wiring between the top and bottom decks.

Just another view of the top deck, but as seen from behind.

A view of the lower deck with the top deck set off to the side.  Note the D12 IR range sensor mounted UNDER the right side of the top deck.  This is the forward looking sensor to detect upcoming walls.

The bottom of the robot.  Shows 2 7.2 vdc NiCad batteries mounted as low as possible to keep the center of gravity low.  The two toothbrush head casters can be seen at the front (left) end of the robot, and a spring loaded toothbrush head at the back to allow going over terrain irregularities (like the non-dead reckoning ramp).  Toothbrushes make very nice casters as long as the robot is traveling over hard surfaces.  They slide nicely, climb up onto objects like ramps easily, are very quiet and act as shock absorbers.  On the other hand, in later years, I found that they were terrible for going over the carpeted floor in expert division as the toothbrush bristles tangle with the carpet fibers causing a LOT of drag.

Bottom with the battery carrier removed.  The black box with aluminum bottom in the upper left side contains the on/off switch, a circuit breaker and a couple of voltage regulators to generate +5 and +9 vdc.  The circuit board on the upper right is the driver for the fan motor. Next to it on the right is a switch which just disabled power to the fan.  The two circuit boards on the bottom carry the LM18201 H Bridge chips.  The D15 IR range sensor is at the lower right side.

This shows how the motor, wheel and encoder are mounted together.

Just another view of the bottom back which shows the spring loaded tooth brush clearly.