Canon 130 Calculator
Canon 130 Calculator Canon 130, released May 1964
The Canon 130 is Canon’s first electronic calculator, design commended in 1962. It was developed in-house, in response to Canon’s optical designers increasing need for lens design calculations. Canon management had a policy in the early 1960s of seeking to diversify from optical applications and electronic office machines were an identified area of interest. The history suggests that an unrelated office machine automation project was cancelled at around the time the optical designers were crying out for help, and the spare engineering team was assigned to develop a desktop calculator.
The resulting machine was released in 1964 and had many features consistent with a first effort by an inexperienced team that was nevertheless backed up by an established technology company.
Architecture
The machine is counter-based, operating in a similar manner to the mechanical desktop calculators that were in use in the early 1960s. The counters are implemented with germanium transistor flip-flops, four flip-flops per digit. This design is logically simple but requires many flip-flops and still more transistors (at least two transistors per flip-flop). It has the advantage of being static and stable in all states, processing can be slowed or stopped and restarted without error, this is useful in development and for troubleshooting. Counter architecture runs into increasing limits as applications move beyond 4-function arithmetic, the architecture is attractive for a simple machine but proves to be unsuitable for more sophisticated development.
User Interface
The 130 adopts the modern (for the early 1960s) convention of a 10-key keyboard. The ‘full keyboard’ was naturally suited to mechanical counter machines but the 10-key layout was simpler and more suited to electronic implementations. The keyboard has keystems that drive individually built-up leaf switches, a design that applies familiar methods despite the need for precise adjustment and the possibility of unclean operation and/or switch bounce. Methods such as magnetic reed switches or precision microswitches have not been used despite having many advantages and being no more complex or costly.
Canon 130 Calculator Edge-lit incandescent displays
The display uses a Canon-designed digit module, said to have been done to avoid the expense of buying Burroughs’ nixie tubes. The Canon module uses thin perspex sheets with dimples drilled in digit patters, one sheet per displayed character. The sheets are edge-illuminated with miniature incandescent bulbs and the dimples scatter the light and illuminate the pattern carried on the sheet. The modules are bulky, depend on all the bulbs being functional, have many soldered connections and require a lot of labor to replace a bulb. An optical company like Canon may have regarded this as a good and familiar solution but from an outside viewpoint the disadvantages are pretty clear.