World’s oldest functioning digital computer reminds us of a telephone exchange

This is the WHICH, the Wolverhampton Instrument for Teaching Computing from Harwell. It is the oldest functioning digital computer and thanks to a lengthy restoration process you can go and see it in person at The National Museum of Computing in Milton Keynes (Northwest of London in the UK).

The system was first put into operation in 1951. It’s function is both familiar and foreign. First off, it uses decimal rather than binary for its calculations. And instead of transistors it uses electromechanical switches like are found in older automatic telephone exchanges. This makes for very noisy and slow operation. User input is taken from strips of paper with holes punched in them. As data is accumulated it is shown in the registers using decatrons (which have since become popular in hobby projects). Luckily we can get a look at this in the BBC story about the WITCH.

According to the eLinux page on the device, it was disassembled and put into storage from 1997 until 2009. At that point it was loaned to the museum and has been undergoing cleaning, reassembly, and repair ever since.

[Thanks David]

Decatron stand-in

Think the swirling glow of a Decatron is cool but don’t want to deal with the voltage issues? [Osgeld] sidestepped the problem by developing a fake Decatron. Admiral Nelson (Captain Morgan’s cheaper cousin) provided the enclosure in the form of an airplane sized liquor bottle. The LEDs are common-something (not sure if it’s anode or cathode) so they end up being individually addressable through the mess of wires coming out the end. This will greatly simplify that kitchen timer we’ve been meaning to build. See the blinking lights go around and around after the break.

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Coachella lamp

This little art piece might be just the thing to add that mad scientist look to your room. It’s called the Coachella lamp and it makes use of several throwback display devices. At the top an Argon discharge lamp puts out ultraviolet light. Protruding from each of the four sides you can see a set of decatrons. There’s also four Nixie tube bar graphs standing tall from each corner of the base. The final touch is the colored glow in the center which is provided by LEDs. We’ve embedded some video of the device after the break.

The lamp is powered by a wall outlet and controlled with an Arduino. We’ve seen deactrons used as timing devices and would love to see some clock functionality added to the lamp. Trying to decipher the time from the different Nixie displays would put this up there with some of those other hard to read timepieces.

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