Distinctive features: The first calculator in a ball-point pen.
Display is 8 digits, red LED.
1.5v (1x N).
160 mm x 15 mm (6.3" x 0.6").
Cost: The initial cost was US$79.95 [about £45 GBP], but this fell to US$19.95 [about £11 GBP].
Made in Japan.
"Calculator doubles as a ballpoint pen
Hosiden Electronics, Japan, has claimed a world first with the development of an 8-digit calculator which doubles as a ball-point pen. Dubbed the "Calcu-pen", the unit is to be exported to the US market where it is expected to be a popular gift item.
In size and shape the Calcu-pen resembles an ordinary ball-point pen, being just a little larger in diameter. The body of the pen contains the display, together with five key switches. These incorporate the calculating figures, four basic arithmetic signs, and a decimal point. The key switches move in four distinct directions, vertically and horizontally, enabling the required number or function to be selected.
Hosiden is a company specialising in the manufacture of keyboard switches and other components for calculators. The Calcul-pen is a result of the company's technological research, although the LSI circuitry is supplied by Sharp Corporation."
The buttons are 4-way switches. To operate, a finger is placed on a button and moved sideways in the direction of the number or operation required.
The journal Popular Science concluded "While the four-in-one design is a clever idea, actual performance is awkward—so is writing with the thick pen".
Advertisement for the Calcu-pen from November 1977, with heavily discounted price.
Click here to see the article "Unusual Calculators The Calcu-pen" by Guy Ball in the "Collecting Calculators" section of this site.
By 1975 the electronics required for a calculator had shrunk so much that it could be fitted into a, slightly bulbous, ball-point pen.
© Text & photographs copyright Nigel Tout 2000-2023 except where noted otherwise.