Exploring The Bendix G-15’s Typewriter

April 10, 2024 by Maya Posch 3 Comments

The Bendix Corporation’s Bendix G-15 was introduced in 1956 as an affordable system for industrial and scientific markets. As with any computer system, a range of peripheral devices for input and output were available, which includes an electric typewriter. Produced by IBM, this typewriter was heavily modified by Bendix, with the version that [Usagi Electric] got their mittens on being equipped with a gigantic 28″ platen. With just power applied to the machine it will even still work as a regular electric typewriter, but it can do much more.

The bits that make an IBM electric typewriter into a Bendix G-15 accessory. (Credit: Usagi Electric)

Most typewriters for the G-15 have a much smaller platen, as can be seen in the brochures for the system. The typewriter is connected together with other peripherals like plotters, card punches and tabulators via a coupler which uses a 5-bit interface. For the encoding on this interface no standard encoding is used, but rather 4 bits are used as data followed by 1 bit to indicate a command. In addition a number of other signal lines are used with the Bendix G-15, which allows control over the punch card reader and run status on the computer from the comfort of the typewriter’s desk.

In addition to the added electronics that communicate with the Bendix G-15, there are also solenoids and sensors which interface with the typewriter’s keyboard. This is what allows for command keys on the typewriter to be recorded separately along with the regular number and letter keys, in addition to the Bendix G-15 using the typewriter to automatically type on the paper. After a good cleaning session the typewriter’s basic functionality is restored, with the hope that once the Bendix G-15 over at the Usagi Farm can power up its DC circuit both will happily chat with each other. Color us excited.

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When Toothbrushes, Typewriters, And Credit Card Machines Form A Band

August 23, 2019 by Roger Cheng 5 Comments

Many everyday objects make some noise as a side effect of their day job, so some of us would hack them into music instruments that can play a song or two. It’s fun, but it’s been done. YouTube channel [Device Orchestra] goes far beyond a device buzzing out a tune – they are full fledged singing (and dancing!) performers. Watch their cover of Take on Me embedded after the break, and if you liked it head over to the channel for more.

The buzz of a stepper motor, easily commanded for varying speeds, is the easiest entry point into this world of mechanical music. They used to be quite common in computer equipment such as floppy drives, hard drives, and flatbed scanners. As those pieces of equipment become outdated and sold for cheap, it became feasible to assemble a large number of them with the Floppotron being something of a high-water mark.

After one of our more recent mentions in this area, when the mechanical sound of a floppy drive is used in the score of a motion picture, there were definite signs of fatigue in the feedback. “We’re ready for something new” so here we are without any computer peripherals! [Device Orchestra] features percussion by typewriters, vocals by toothbrushes, and choreography by credit card machines with the help of kitchen utensils. Coordinating them all is an impressive pile of wires acting as stage manager.

We love to see creativity with affordable everyday objects like this. But we also see the same concept done with equipment on the opposite end of the price spectrum such as a soothing performance of Bach using the coils of a MRI machine.

[Thanks @Bornach1 for the tip]

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Typewriter Types, Plays Music

June 27, 2015 by Adam Fabio 9 Comments

[Chris Gregg] had a dream. He wanted to convert use a typewriter as a printer. Sure this has been done before, but [Chris] wanted to create his own version. He picked up a 60’s era Smith Corona electric typewriter, with the hopes of driving its key switches with a computer. You can imagine his surprise when he discovered the keys were not electric switches at all, but a complex mechanical system which triggered a clutch to strike the actual paper. Realizing this was not going to be a simple wiring job, [Chris] set the project aside, where it remained for several years.

A conversation with [Bruce Molay], a coworker at Tufts University reignited [Chris’] interest in project. [Bruce] suggested using solenoids to press the keys. [Chris] dove in, and quickly had 48 solenoids on hand. The first problem was mounting the solenoids on the keys. [Chris’] roommate happens to be [Derek Seabury], president of Artisan’s Asylum Hackerspace. [Derek] created an acrylic frame which holds the solenoids and fits directly over the typewriter’s keyboard. This meant that no modifications needed to be made to the typewriter itself. Simply lift off the solenoid array and you’re ready to rock like it’s 1965.

The next step was driving all those solenoids. For that, Chris worked with [Kate Wasynczuk], one of his students at Tufts. [Chris] designed a board using Texas Instruments TPIC6A595 shift registers. The TIPC “power logic” series work like regular 74 series logic, but have seriously beefy outputs. These chips can handle up to 50 volts and 1.5 amps pulsed output current – plenty for [Chris’] 24 volt solenoids. [Chris] taught himself schematic entry and PCB layout in Eagle. After only two tries, he had a working board from OSHPark.

An Arduino Uno converts serial over USB output to a bit stream ready to clock into the shift registers. On the computer side, [Chris] wrote up a basic CUPS driver which allows him to print from his Macbook. The perfect demo for this project turned out to be musical. Click past the break to see The Smith Corona perform “The Typewriter Symphony”, by Leroy Anderson. This may be the first time this particular piece of music has been performed with actual words being typed, rather than random keys.

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