This piece was built late in the series chronologically, however I reserved the MK I designation for the day that I located the nixie tubes that display the numbers in this piece.  Nixie tubes are vacuum tubes filled with neon, and are possibly the very first form of electronic numeric display technology.  I deliberately made the piece to look old by simulating the look of black Bakelite and using Oak wood. I made a vintage style label from a circuit board and used old style indicator lamps to complete the antique effect.

I engineered the control circuit to change the numbers at random intervals, occasionally turning them on and off to create movement and patterns in light.  Since the numbers are stacked inside the tubes there is also a vertical movement within the tubes when seen from the side. (see below)  It is interesting to note that I use contemporary microcontroller technology to operate these displays.

CONSTRUCTION NOTES



NIXIE TUBE DISPLAYS

In a Nixie Tube display each numeral is a complete, lighted cathode in the shape of the numeral. The cathodes are stacked so that different numerals appear at different depths. The anode is a transparent metal mesh across the front of the display. 

The tube is filled with the inert gas neon with a small amount of mercury. When an electric potential of 180 to 200 volts DC is applied between the anode and any cathode, the gas near the cathode breaks down and glows with an orange-red color.

The name Nixie came about accidentally. A [Burroughs] draftsman making drawings of the device labeled it NIX I, for Numeric Indicator eXperimental No. 1.  His colleagues began referring to it as "Nixie," and the name stuck.  (Scientific American, June '73, pp. 66).

PILOT LAMPS

I also searched through piles of surplus parts to find the perfect vintage indicator lamp for this piece.  Here is the complete part: