A project I started some time ago (2007 ?) with the purchase of four aircraft indicator units. I have no idea what they where intended for, but they came new in a vacuum sealed bag. Their production date is somewhere in the early 70's
With the displays from four of these units I was able to construct three clocks ( each unit had three 0-10 displays and two with letters and combined numbers )
The displays are of the projection type in a really small form factor.
The left meter shows seconds ( each thick mark is a second ) and the right one does a full minute from bottom to top.
The pot sets the display and backlight brightness and the switch is used to set the time ( I didn't want to alter the clock externally, the only change I made is a hole for the power connector in the place where a grounding screw used to be.
The whole thing is controlled by a Atmega8 ( probbably a bit overkill ) and timekeeping is done with its internal RTC clocked buy a dallas DS32KHz TCXO. The meters are both center zero and are PWM driven by the uC
It uses an external 12V wallwart and that volage is stepped down with a switching regulator for incandescent lamps (variable with the panelmount pot )
Hope you guys like it, I'm verry happy with how it turned out.
They had 20+ units at the time and if I had known back then there would be interest in these things a probably would have bought a few more I contacted the seller recently only to find they where all gone.
These units being aircraft grade have every position fitted with lamps where only a small numbers was being used, so together with the lamps from the dismantled unit that gives a lot of spares of the probably not so easy to find bulbs.
The backlight uses a 1W midget flange bulb and it's lampholder is located under the "R", on my unit I discovered that the plastic color filter was discolored and warped by the heat of the bulb, so I made a LED replacement for it.
I have three working units, one sits on my desk the second one I sold a while back and the third one is still available. I might put up an ebay auction for that one.
Anyone who is interested in one can contact me before I do.
More info ... I have a few pictures from the early building stages.
The original displays ( not in the correct order )