Kevin Santo Cappuccio's In-Car Compass Upcycles a Soviet Plasma Display with a Sensor Fusion IMU
"You can either rub a magnet on a needle and float it on some water, or a 10 DOF IMU and a 94MHz sensor fusion coprocessor."
Maker Kevin Santo Cappuccio has turned a vintage Soviet-era plasma display into a Fallout: New Vegas-inspired in-car compass, offering at-a-glance direction information in a friendly glow.
"[I] finally got this IGV1-16/5×7 Soviet plasma display compass working. I seriously underestimated how much is involved with getting a compass heading," Cappuccio writes of the project. "Like, you can either rub a magnet on a needle and float it on some water, or [use] a 10 DOF [Degrees of Freedom] IMU [Inertial Measurement Unit] and a 94MHz sensor fusion coprocessor."
The display in question is a Soviet clone of a Burroughs Self-Scan plasma display, a single-line dot matrix which glows cheerily to display information. At least, it should — but the components for driving it have long since become unobtainable. Using Burroughs' documentation — the Soviet equivalents being hard to find and, naturally, written in Russian — Cappuccio was able to build a custom driver board, after discarding the idea of using Nixie drivers.
"I just used STX616 high voltage NPNs (or MPSA42 work too) to drive them. Basically it's some high voltage transistors as open drain for the seven rows and the three scan cathodes," Cappuccio explains. "The blanking line is the same but it only gets pulled down to 82V with a Zener [diode]."
Driving the driver is an STMicroelectronics STM32L432KC Nucleo 32 development board with a Pesky Products USFSMAX high-accuracy absolute orientation estimation module — which packs its own coprocessor in order to take the strain of squeezing ten different measurements into an accurate heading off the host device. A 3D-printed housing finishes the build, which blends neatly into the interior of a Jeep.
More details on the project are available in Cappuccio's Hackaday.io project page, with source code available on GitHub under an unspecified open source license.