Interactive Drawing Machine

After the demise of Interscan in 1978, many of the Lovelight team members continued their pursuit of the burgeoning laser show market. One of the engineers had the idea that the process of making laser drawings would be dramatically improved if the X-Y coordinates of the drawing could be adjusted while viewing the laser display. Moreover, a drawing might even be created by a person who lacked freehand drawing skills, by tracing conventional artwork with the laser projection.

Some of the Lovelight artists argued that such a machine was impractical because it would not allow a trained artist to utilize their manual drawing skills. Of course, all the nay-saying spurred the engineer to prove them wrong, and by the following year he had completed a "proof of principle" machine. The device consisted of 256 precision slide potentiometers, arranged in 128 consecutive X-Y pairs. Each pair controlled a single point, or coordinate, of the drawing. Beam blanking for each point was controlled by 128 dedicated toggle switches. A 128-pole digital stepper switch sequentially sampled the array at an adjustable clock rate, outputting the slide pot and switch positions to the X-Y scanners and beam blanker.

The machine was sold in 1979 to Laser Creations, Inc. of Denton, Texas. Under U.S. patent law, the operational principle became public domain one year later.

Below:
Rear view showing the internal components. The large PC board in the center is the TTL digital stepper switch. The surplus components used to build the machine cost less than $300.

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