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Enigma-E expansion kit

When the Enigma-E was introduced to the public in 2003, it was an instant success that no doubt has helped to raise the overall interest in historical cipher machines and that of the Enigma in particular. To celebrate the fifth anniversary of the Enigma-E, we developed a nice expansion kit.

Introducing the UhrBox-E: a self-build electronic kit that replicates the infamous Enigma Uhr, an Enigma add-on that was introduced in 1944 by the German Luftwaffe (Air Force) in an attempt to improve the security of the Enigma cipher.

The image on the right shows what the UhrBox-E looks like when it is completely assembled. It should be connected to the Steckerbrett of the Enigma-E. At the center is a rotary switch that is used to select any of the available 40 settings.

A 2-digit display shows the current setting from 00 to 39. Twenty 'flying wires' are used to connect the UhrBox-E to the Enigma-E's plugboard. The device is powered by a four AA-size batteries (not included). The device was thought to enhance the Enigma's security, but in reality operator mistakes gave it away almost from day one, as you can read in the enclosed manual.

 See how the UhrBox-E was developed

What's in the kit?
The kit consists of a double-sided 9 x 9 cm PCB complete with all electronic components, resistors, capacitors, micro-controller, display, cable, plugs (Steckern) and even a battery holder (not the batteries themselves). At the centre of the PCB is a so-called rotary encoder which simulates the large 40-step dial of the original Uhr.

The UhrBox-E comes with a full-colour 36 page A5-size manual of the same quality as that of the Enigma-E. It contains detailed instructions on how to build the UhrBox-E, but also explains the working principle of the mechanical original and the historical context in which is was used.

The UhrBox-E also comes with a new micro-controller for your Enigma-E in order to make older versions compatible with the UhrBox-E. It contains release 1.50 of the firmware in which all currently known bugs have been fixed.
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Please note that, in order to make use ofthe UhrBox-E, you also need to have the Enigma-E kit. It can be used with all versions of the Enigma-E. Check the images below to see what the manual is like. It is printed in full-colour and contains images of a real Enigma Uhr plus an 'exploded view'.

Improve your UhrBox-E
Build your own wooden case

Depending on your woodworking skills, you may be able to make a suitable wooden case for your UhrBox-E. Although we have not provided the drawings for a case in the manual, with a bit of engineering you should be able to create a good looking enclosure, such as the one shown here.

The PCB of the UhrBox-E is scaled to the same aspect ratio as the Enigma-E, so that the two kits fit well together. The case shown here was created by Austrian collector Günter Hütter.

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In the image on the right the UhrBox-E is shown next to the Enigma-E, which is also housed in an enclosure that was made by Günter Hütter. The case of the original Uhr has been copied to the finest detail, and it even has the metal hooks for clamping it to the side of the Enigma machine.

The Uhr is connected to the Enigma by means of 20 patch cables, which are here made of shoe­laces. If you compare this setup with that of the real machines, you'll see that we are not far off.

 See how the UhrBox-E was developed
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Crypto Museum. Last changed: Tuesday, 24 May 2016 - 15:27 CET.
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