The Century of Light  is the first use of a microprocessor in a public sculpture.   It uses technology from 1979.  In fact there is an article in an issue of Archeology magazine (!) about the same microprocessor chip.   A Sym1 6k 1 meg clock microprocessor board and memory, including three custom designed "sensory" printed circuit boards ( light, sound  and radar) which control 9 custom "Light boards." These light boards operate 144 opto-isolated solid state relays powering the incandescent lights of the large mandala outdoors.  .  All this, in a standard rack cabinet about 2 x 2x 7 feet, weighing approximately  250 lbs.  Except for the solid state relays, these very same electronics are in the PROGMOD

City Worker Vasquez and Jim Zalewski in the pump room preparing to remove the rack cabinet.  The "DANGER  4800 VOLTS"  was the artist's way of asking  workers not to disturb the locked cabinet or its contents.
Note In the image to the right, notice the gray water line on the cabinet's wall from one of the two floods that occurred when inept workers drained the pool into the pump room.  Jim Zalewski observed that the century of Light artwork became a very expensive electro-plating unit and deposited its copper circuit traces on the walls of the cabinet.

This is the interior of the cabinet in the underground pump room west of the fountain's pool. The Sym1 microprocessor is the top unit.  The multi colored cable is connected to the "Kluge-a-face" board.  this board is a unit that conditions the Sym1's output and corrects  for some errors in the desifgn of the sensor and light boards. The nine ribbon cables carry signals from the  light control boards to the solid state switching relays below. The power supply for the electronics with its fan can be seen below the rack of sensors and light boards.

The microphone was housed in this protective cage.  It was disconnected when senior residents of the nearby apartment building complained
that passing motorists learned that they could activate the sculpture by beeping their car horns.

These are the 144 solid state relays that supply the
 60 watt incandescent lamps that comprise the mandala's display.  
Until it was discovered that each relay contained a hidden fuse,
darkened lights were a serious mystery.

Attached to the column's right side, the small cylinder angled down to watch the area in front of the fountain is a Doppler radar unit that senses the size/speed of anything in its field.  There is also a photo cell in the cylinder that senses day
or night.

Photo cell, light control and radar circuits designed by Rene Vega and laid out by Jim Pallas

Renee Vega working into the wee hours -1979

  Above: a sample of the incredibly elegant language Mims created to control the lights.  With minimal instruction a child can write code to sample the sensors and program the mandala's behavior. Programming can be done on the PROGMOD and ported to the Century of Light.

Randy Mims working a Whee! moment in 2006

When city inspectors asked for a drawing of the steel structure of the mandala, they were incredulous that Pallas intended to build it with out a drawing. by simply laying the parts out on the floor and welding them together.  They insisted on a drawing of a "typical cross-section" of the structure.  Pallas explained that there was no typical cross section. and convinced them that they could get the information about the integrity of the structure from a scale model  -above and left-  that he would provide.
The mandala was welded from 1" square steel rod with 8" hexagonal discs on which to mount the lamps.

Pallas attaching the 12" acrylic globes.  With the  plastic globes and the ready availability of fist sized stones in the pool, there was much talk of possible vandalism.  The only "vandalism" occurred when the sponsor of the artwork insisted on mounting a bronze tablet  on the side of the pool. Pallas advised substituting concrete or stone
- something of no intrinsic value- instead of bronze.  The sponsor insisted on bronze and claimed it would be securely mounted to the pool's side.  It disappeared in a week.

The mandala was hoisted to the top of the support column and bolted to a n 18' column 12' in diameter.

Century of Light: Six minute video

PROGMOD :Off-site programming module

Technical: Information and images of the Century of Light

Proposed:  Demonstration of the mandala

Animated Rendering: Temporary mandala on a building

Labyrinth: Futile attempt to save the artwork.