
Admittedly there's not much information here yet! I have been promised some stories about the interesting art of hacking calculators, but if you know of any examples or articles, please submit them!

Hacking It!

I was delighted to receive a letter from Poor Mike asking me if I was aware of the use of modified Russian calculators for other than their intended purpose. Of course, I wasn't - but putting together information from Mike (who at one time developed such devices), Sergei and other contributors to the site, we can begin to build up a picture of some of the uses to which these modified calculators were put.
^{© Sergei Frolov}
remote!
Radio [magazine name] for beginners.

It appears to have been reasonably common for Soviet calculators to be put to use for unusual purposes, be it as a make-do intercom system for an emergency hospital ward, or as a counter, timer, remote control, game, multimeter, etc. Some hackers (and I use the word in its noblest sense) even added math functions to their machines! Such modifications are rarely, if ever, heard of in the West!

Typically, the modified calculator retained its basic functionality; the modifications were an expansion of the calculator's possibilities. It appears that several machines were specifically designed for (or at least, allowed) upgrading and modification, something not apparent in Western machines of the time. And, of course, many Russians had a need for such modifications - it was often not possible to go out and buy a better calculator!

The picture here shows the cover of a magazine which shows a B3-34 calculator interfacing to some homebrew electronics and controlling a model tank! Fascinating (and fun, I'm sure) stuff!

B3-23

^{© Sergei Frolov}

B3-23 modification.

B3-34

Cassette Modification

The B3-34 was a popular machine for hackers, probably due partly to its programmable nature, and partly due to its relative availability. The machine was not specifically designed for expansion, but as evidenced by the pictures on this page, expansion was quite possible.

During the early era of programmable calculators (say, before the 80s), various methods of storing programs and data were tried. Typically, though, storage was not available and one would have to re-enter any stored program if you had turned off the machine. This became rather inconvenient, and the MK-47, introduced magnetic cards for storage of programs and/or data (some Western machines; Texas Instruments TI SR-52, TI-59 and the Hewlett-Packard HP-65, HP-67, HP-41C and others, also used magnetic cards for storage). Another method of storing programs was to use a standard cassette deck, and some Western machines used this method (some Casio machines, for example - the FX-502P). Some machines in the West introduced CMOS memory, which retained programs even when the machine was turned off (the TI-58C, produced in about 1977, had this capability - and was essentially a TI-59, sans card-reader).

^{© Sergei Frolov}
B3-34 cassette
Cassette for storing/loading programs.

^{© Sergei Frolov}
cassette interface
Inside the modified machine. The insert shows the expansion interface that has been added to the left side of the machine (in face-up view), for the cassette communication.

Apart from the MK-47, though, there appears to have been no Soviet programmable calculators which had the capability to store their programs/data when they were switched off. The pictures above come from the magazine "Radioyear-book", 1989, and show a B3-34 calculator which has been modified to include cassette storage!

The modification seems to consist of a small expansion interface which allows communication with a cassette unit; the picture shows an insert with this area of the calculator enlarged.

Generic Device Controller

^{© Sergei Frolov}

Controller Circuit

The diagram to the right is from an article in 'Radio, No. 12, 1990', which details how to build a generic controller which can be driven by the B3-34 machine.

'The circumscribed below prefix to the microcalculator B3-34 allows program to control devices with small speed ˜ by every possible models and controlled toys, light - dynamic daisies, projectional equipment etc. The complex the programmator - microcalculator can be for the phototiming controller. At compilation of programs it is necessary to take into account specificity of operation of controlled devices. The principle of operation is based on recognition of the sign written in defined bit of the indicator of the microcalculator.'

MK-61

Measuring - computer complex IVK-3/TO

The measuring - computer complex IVK-3/TO is fulfilled on the basis of the programmed calculator, for example, MK-61. Its structure is entered by(with) the programmed microcalculator, interface block fulfilled in one tank as the completed instrument and a set sensors of different values.

More information about this device is contained on the MK-61 page.


Bob's letter really made me laugh. I like getting email like this! These sorts of stories really bring home the situation in many areas of the former Soviet Union.

Hospital Call-Button

"When I was in Sankt Peterburg working in a hospital, I was asked to "fix" a patient call-button / intercom system. Really, one of the Russian staffers had been to their stateside partner hospital and seen something modern. They didn't want theirs fixed, they wanted me to magically turn it into some state-of-the-art US model.
Anyway, I could improve it a little, as it had been very poorly designed. When the patient pushed the call button, an LED was illuminated on a unit at the nurses' station. However, the LED was down below the panel, so you had to be standing right above the unit and look down into a hole to see which was illuminated. I managed to disassemble it, enlarge the holes where the LED's were supposed to go, and reassemble it in a more useful configuration. I could do nothing for the completely unintelligible noise you got in place of the patient's voice, however....
The calculator-relevant angle is that the maker of hospital patient intercom systems simply used calculator bodies! It was a unit kind of like the B3-05 or MC-1103. The display panel was missing, of course, they had only used the plastic shell of the calculator. A long and narrow speaker was mounted there, with a cloth-covered grill covering it. The keypad was completely missing, and the space normally occupied by keys was covered with a metal panel with a row of sixteen (tragically undersized) holes above the LED's. A push button on one side allowed the nurse to "talk" back to the unit in the patient's room, which was just a simple small plastic box with one button and a speaker. As I mentioned, however, they might as well have simply used buzzers in place of speakers.
Afraid I didn't take careful notes of the exact details, I didn't imagine that anyone would be interested!"

- Bob Cromwell

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