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Calculators: Handheld: Kosmos 1

Size (approx):

70mm x 140mm x 27mm (w,h,d)
Weight 116g excluding batteries


4.5V DC, 3 x AA size batteries.  It accepts an adapter (DC 4.5V, 0.36W) through a socket on the top side in the middle.  The on/off switch is on the left hand side in line with the biorhythm chart.  Battery lifetime is quoted as 10 hours for dry batteries.


Slightly curved upwards case made from two-piece black matt plastic construction.  The top area is dominated by a large aluminium panel printed in four colours with the brand and model number but more importantly the biorhythm look up table.  The green display filter is flat, slightly proud and gives a good clean display.  A set of six red and orange discrete LEDs are housed within the printed table.  The recessed keyboard has its own white plastic escutcheon. The keys are long travel and squishy but work well.  The whole thing looks like a Texas clone but feel heavier and better quality.  The rear has a large metallic sticker with a handy Biorhythm PSI chart.


8 digit green VFD with a ninth digit for negative and error indication


4 function calculator with biorhythm functions.




Kosmos International Ltd., made in Japan.  Serial number 7046046B



Quality feeling machine that is a very basic calculator focussing on the fashionable Biorhythm rage at the time.  The original case is soft light brown felt-effect with an open top and front pocket for the manual.  The logic is OK with good recovery and only let down by the negative zero bug.  The biorhythm functions are not Y2K compliant.


1 x cpu: Texas ZA0541 K8 7714 (date code week 14 of 1977), 28 prin DIL, 0.6" width
1 x 9 digit VFD unit: single tube flat front Futaba 9-ST 20 6D (April 1976)
6 x discrete LEDs
7 x transistors
14 x diodes
8 x capacitors
18 x resistors
2 x resistor arrays
1 x transformer


The keyboard assembly (Kosmos-1 CA2446-03) rests on top of the battery compartment and is joined to the main cpu board via 12 strong copper wires.  The display board sits piggy backed on the main board and is populated with a few extra components.


It is very difficult to prize apart the case that is held together by internal lugs only.  You need to push the rear section sides in to pop the lugs but damage is very likely so I would not recommend it.  Eventually the front can be lifted off.

Logic comments:

The (CLR) key is used once to clear the last entry of a number and a second time clears the whole calculator.

Overflow on number input is suppressed inputting a ninth digit is ignored

Negative numbers are shown with a “-“ in the far left (ninth) digit thereby allowing full eight digit negative numbers.

An overflow shows zero and “C” in the far left (ninth) digit and is recoverable using the (CLR) key

Divide by zero shows zero and “C” in the far left (ninth) digit and is recoverable using the (CLR) key

There is automatic constant on all four functions

It suffers the negative zero bug; try (1)(-)(2)(=) to give “-1” now (+)(1)(=) will give “-0”

To find out your day of birth key in: (M)(M)(D)(D)(Y)(Y)(B1) will then display the day of the week [1=Monday].  You can use (B2) to enter another birthday to find your compatibility by ending with (C/S) the compatibility/Similarity key.  

For biorhythms key in today's date [in the twentieth century]: (M)(M)(D)(D)(Y)(Y) (DATE) then your birth date (M)(M)(D)(D)(Y)(Y)(BIO) and lights will start to glow.  You can go back (<R) and forward (>F) on today's date to examine your rhythm. 


The box measures 100mm by 157mm and is 43mm deep so just about accommodates the calculator in its case.   It is printed in silver, black and three primary colours.  There is a card former on the inside which keeps the whole thing rigid.  Construction is top tuck-end and envelop base. Printed in Japan.  A great design that looks like something from “The Tomorrow People”.

The original (not shown but 145mm x 69mm) Warranty card is four pages in black only and interestingly asks for your date of birth and occupation.


The manual is probably one of the neatest I have ever seen – and yes, it does have a picture of the back on the back!.  It measures 61mm by 119mm with 56 pages, a lot of which are full four process colour!  The pages are colour coded with a background colour and key lines.  About two thirds of the (English only) pages are devoted to biorhythm examples, philosophy and an extensive bibliography. It even has several pages to note down people’s birthdays.

 Quote: “Congratulations.  You’ve just shown the good sense to buy the best pocket-size biorhythm computer on the market.”

 Quote: “It can also add, subtract, multiply and divide.”

manual page 3

manual page 4

The two images on the left are in the "Introduction to Biorhythm" section of the manual. IBM 360

The IBM 360 computer can give you all the biorhythmic calculations you want.  It's as big as a room and costs about $2,000,000.
manual page 9
The images on the right are two more pages convincing you that you've made a good buy. Biocom 200

The Biocom 200 computer can monitor your biorythm, too.  It takes up most of a desk top and costs about $3,000.
manuak page 19

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