The Final image of the Bombe Nixie clock from Bad Dog Designs. Photograph courtesy of Peter Gardner Photography


Limited edition run of 10 All 10 Bombes have now been sold

So, the starting point for the clock, Alan Turings 'Bombe' A giant electromechanical device to help British cryptologists decipher Enigma Machine encrypted messages during WWII - built in 1939 at Bletchley Park.

The Machine was since rebuilt by the Welchman / Turing Rebuild trust, lead by John Harper Read more here who after speaking to on the phone, kindly agreed to let me use some of their original Drawings.

However, not all the original drawings suited my needs so quite a few had to be redesigned. My drums are belt driven as all the gears on the original machine are very noisy! this is a clock for the home and needs to be quiet.

The first physical parts that I made were the distinctive little clips that are used to hold the drums onto the drive spindles. I had these laser cut from 1.5mm steel, and then they were sent off to be nickel plated.

As the build progressed, more parts were finished. Here you can see the machined Aluminium drums, and the Nixie clock electronics in the background with the stunning RZ568M Nixie tubes, hand made by Dalibor Farny

The Engraved lettered front disc, along with the drive plate, clips, springs. Even the little screws that hold the front disc to the drum have been machined from the original drawings, every detail as authentic as I can get it.

The clock has some custom electronics I developed, so when all 4 drums are in a specific position it will chime. This was done with hall effect sensors and little magnets embedded in the drums. I then made a PCB for all the circuitry.

This is a Single drum on test. There is a brushless motor for each drum, so they are quiet and very reliable. A lot harder to use than regular motors as each one needs it's own drive electronics.

With my custom electronics all ok, and the motor drive system looking good - it was time to wire up all the circuit boards on the back of the front panel. I like my wiring to be neat and tidy so everything sleeved and connectorized!

Casing all finshed, it was originally an old resistance box that I reused. The clock electronics on test and you can see the spindles mounted on the front of the box that the drums locate onto.

Some of the little finshing touches, a brass label on the top saying 'Bombe' done in the same style as the 'Enigma' badge on the machine that the Bombe was designed to defeat!

The finished clock down in London at Pete's photography studio. As you can tell from the large picture at the top of the page, a lot of time and trouble was taken to get everything just right!

This is a very brief overview of some of the steps that were involved in the making of this clock. I could not have done it on my own, and first and foremost would like to thank John Harper for agreeing to let me have the drawings. Olly Kinsley at OKR for machining the drums, Steve Bean at SNS for the many layers of fine paint! Dalibor for the wonderful Tubes and also Pete at PV for the clock electronics. Andy and Mandy for the engraving on the top and front plates, John Smout for laying out the PCB's.

  • Hours, Minutes and Seconds display on six Z568M Nixie Tubes
  • 50mm (2") digit height
  • DIRECT DRIVE = Noise Free
  • Temperature display in Celsius or Fahrenheit
  • Double dot colon neon indicators with many configurable modes of operation
  • 12 or 24 hour modes
  • Uses a Quartz Crystal Oscillator as the timebase
  • Programmable leading zero blanking
  • Date display in either DD.MM.YY, MM.DD.YY or YY.MM.DD format
  • Programmable date display each minute
  • Scrolling display of date or standard display
  • Alarm, with programmable snooze period
  • Optional DCF / MSF / GPS synchronisation with status indicator LED
  • Dedicated DST button to switch between DST and standard time
  • Supercapacitor backup. Keeps time during short power outages
  • Simple time setting using two buttons
  • Programmable leading zero blanking
  • Five programmable neon colon settings (Flashing AM/PM indication, illuminated AM/PM indication, both flashing, both on, both off)
  • Seconds can be reset to zero to precisely the set time
  • Programmable night mode - blanked or dimmed display to save tubes or prevent sleep disturbance
  • Rear Indicator LEDs dim at night to prevent sleep disturbance
  • Weekday aware ‘Master Blank’ function to turn off HV/ tubes on weekends or during working hours
  • Separate modes for colon neons during night mode
  • Standard, fading, or fading + scrollback display modes
  • ‘Slot Machine’ cathode poisoning prevention routine
  • Programmable RGB tube lighting – select YOUR favourite colour palette
  • 729 colours possible. Have a different colour of your choice every hour, or autochanging colours
  • Not AC frequency dependent – works in all countries
  • All user preferences stored to non-volatile memory
  • The Clock measures just over half a Meter long (505mm) by 250mm tall and weighs in at 10Kg.

  • The clock took about 5 months on and off to complete, from initial request to the finished thing. I greatly enjoyed the challenge of putting something like this together, the late nights, the endless cups of tea and bags of Haribo! The research and quite a few flashes of inspiration to work out how to make certain things work :)