Story Teller, Model 423 Robot Calculator and XYZ Box
completed March 2003

The clumsily-named Model 423 controls two different devices, a typing-robot assisted 1952 Victor Calculator and a WPS Model 7052b analog plotter (a modified HP plotter). Most of my boxes control only one device, this is an experiment.

Mechanically it doesn't please me very much, but you win some and lose others. Electronically it's fairly complex, probably the most complicated PIC device I've made so far (things seem to be escalating).

Basically, the calculator prints numbers and tallies them up on a long roll or narrow paper, with a big crunchy mechanical clatter. The plotter is a little more flexible; it can print paragraphs of text or draw freeform pictures on an ordinary sheet of paper. (A lot of complex pre-processing is done offline to generate the character stream stored on the tape that does the writing and drawing.)

As do all the Story Teller components, the Model 423 listens to a character stream provided by the Model 3 Tape Reader, from stories punched onto the perforated paper tape, described elsewhere. It listens for two record types, V for the Victor calculator and X for the XYZ Flutterwumper command stream for the analog plotter (said Flutterwumper scheme conjured up by Don Lancaster) and when it sees a record of the appropriate type, interprets the data and makes the appropriate object dance (sing, waste paper, etc).

The Victor Calculator is an amazing thing. A fairly ordinary electric/mechanical calculator of the time, this one has a typing robot attached to the keyboard. The calculator came from the Los Alamos National Laboratory, and was likely intended as a primitive data logger (the intent was logging, not primitiveness) for some apparatus or other that needed to record long strings of decimal numbers. Multi-channel analyzers come to mind... basically the calc has specially-made solenoids mounted over the ten digit keys and plus and minus; when the appropriate power is applied to a solenoid for the appropriate time interval the calculator operates. Transforming ASCII characters to calculator key presses is pretty easy.

The analog plotter tediously writes text, stroke by stroke, driven in X and Y by a pair of analog voltages generated by a pair of DACs (digital-to-analog converters) within the Model 423. That part is more or less straightforward; however nothing else about the plotter system is. Text is converted to a series of "turtle graphic" type commands, run-length-compressed about 35:1 and punched on the paper tape. Arbitrary images are more complex; they start out as PostScript generated by Gimp or Illustrator or somesuch. The EPS file is then processed with a PostScript program (as Don Lancaster points out, PostScript is a full programming language), then run-length encoded and punched to tape. Images get bulky very fast, so simplicity is required. It takes about four feet of tape (about 400 characters) carefully scratch out a 3-inch circle to 100 DPI resolution.



mixed media (steel, paint, electronic components) 6"h x 8"w x 7"d, approx. 2 lb.