In recent decades we have seen a wide variety of calculators with sober, efficient, novel, and even outright crazy designs. The benefits of miniaturization have allowed us to turn calculators into simple gifts (as is the case of the diskette calculator), but they also gave rise to slightly more practical hybrids. One of those hybrids was the Calcu-pen, a calculator that went on sale in 1975 and was as compact as a pen.
I remember very well that one day, in elementary school, calculators integrated into rulers and pencil cases came out of nowhere. They exploded almost the same way as the yo-yo or the tiki-taka, and everyone had to have one. Of course, the craze for those calculators disappeared just as quickly, but evidently there was something special about them.
Needless to say, calculators on rulers precede my old school memory, and are the product of great improvements in manufacturing methods and miniaturization. Today, the idea of carrying a compact calculator in your pocket seems obsolete compared to software solutions offered by smartphones and the Web itself, but what if that calculator were something more? A pen, say.
The Calcu-pen
That leaves us with the Calcu-pen, a curious calculator that dates back to 1975. According to available information, Calcu-pens were manufactured in Japan, and hit the market with an original price of $79.95, but in less than two years they received two consecutive 50 percent discounts, first to $39.95, and then to $19.95.
The Calcu-pen interface features an eight-digit red LED panel, and five directional keys to access all symbols. The Calcu-pen measures 160 millimeters long and has a diameter of 15 millimeters, so it's possible to work with it, but it doesn't offer the best experience. The size is associated with the type of battery it uses: A type N cell, also known as LR1 alkaline, or E90 (Energizer designation).
The Satolex Variant
In the early 1980s another variant of the Calcu-pen appeared, this time under the wing of the company Satolex. Its design includes a physical power switch, 19 buttons, and an LCD panel replacing the classic red LED. There are conflicting reports regarding the original manufacturer of the Calcu-pen. Some believe it was the same Satolex company, but nothing is definitive. The first model is quite hard to get these days, while the LCD edition usually parades on eBay with an average price of $30.
