Cockpit Instrument Respectfully Retasked As A Clock

How do you convert an old cockpit instrument into a clock? Easy: just build a circuit that convinces it it’s in the air, and the rest will take care of itself.

Now obviously, little about [porkfreezer]’s conversion of King KI 266 DME into a clock was actually easy; working with avionics rarely is. DME stands for “Distance Measuring Equipment,” an instrument that’s part of the radio navigation suite of many aircraft. DME measures the line-of-sight distance of a plane to a ground station by measuring the time it takes for a signal to return after the plane interrogates it. The plane-mounted equipment includes a UHF transceiver and a display for the cockpit instrument panel, which accepts an analog voltage signal from the transceiver and translates it into a readout on the nice Panaplex digital display.

Rather than gutting the thing and just driving the display directly, [porkfreezer] decided to build a circuit to generate the proper signals for the DME. The board uses a PIC16 and an MCP47C dual 10-bit digital-to-analog converter to generate the voltages needed, while a USB-powered DC-DC converter provides the ±15 volt supply the DME display expects.

Everything lives on a PCB that fits right on the back of the instrument. Sadly, the connector needed to mate up to the one on the instrument was outlandishly expensive — again, avionics — so [porkfreezer] had to solder the board directly to the DME’s pins. Otherwise, this would have been a completely reversible hack.

Still, it’s an interesting reuse of an unusual piece of gear, and one that respects the original design as much as possible. That counts as a win in our book.

World’s Largest “Nixie” Clock At World Maker Faire

World Maker Faire was host to some incredible projects. Among the favorites was Nixie Rex [YouTube Link]. Nixie Rex is actually a Panaplex display, since it’s glow comes from 7 planer segments rather than 10 stacked wire digits. One thing that can’t be contested is the fact that Rex is BIG. Each digit is nearly 18 inches tall!

Nixie Rex was created by [Wayne Strattman]. Through his company Strattman Design, [Wayne] supplies lighting effects such as plasma globes and lightning tubes to the museums and corporations. Nixie Rex’s high voltage drive electronics were created by [Walker Chan], a PHD student at MIT. Believe it tor not the entire clock runs on an ATmega328P based Arduino. The digits are daisy chained from the arduino using common Ethernet cables and RJ45 connectors. A Sparkfun DS1307 based real-time clock module ensures the Arduino keeps accurate time.

[Wayne] and Rex were located in “The Dark Room” at Maker Faire, home to many LED and low light projects. The dim lighting certainly helped with the aesthetics, but it did make getting good photos of the clock difficult. Long time Hackaday tipster [Parker] graciously provided us with a size reference up above.

Click past the break to see a closeup of that awesome cathode glow, and a video of the Nixie Rex  in action.

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