JC Uses a Raspberry Pi and an Old Radar Tube for Impressive ADS-B Visualization

Electronics hobbyist and licensed pilot JC has built an ADS-B monitoring system with a difference: it sends it output to a legitimate radar scope cathode ray tube (CRT), for true authenticity.

"In this project, I built from my mind a power supply and deflection amp circuit for my 5FP7 radar scope CRT to use it as an XY scope with that pretty P7 phosphor," JC explains. "My end goal being that I wanted to make a radar scope with it, but until then I simply displayed some vector graphics on it."

While the overwhelming majority of modern displays are based on liquid crystal panels or LED matrices, there's still a lot of love around for the vintage cathode ray tube (CRT) — where an electron gun fires at a phosphor-coated display in order to create a glow which persists until the next pass. It's such an iconic visual for radar sweeps and oscilloscopes that it's often emulated in software for use on modern display types — but that wasn't enough for JC.

Once JC had figured out a way to interface with the tube, taken from an old radar display system, he set about trying to build a suitable circuit "out of as much junk as I could find, with the exception of a few slightly more specialized parts such as the deflection amp's output stage." The project also called for a flyback transformer, built from a 3D-pritned spool with a drill chuck attachment to make the high-voltage winding process less onerous.

Once an image was possible, JC added a Raspberry Pi single-board computer — initially to generate vector images suitable for showing off the display's capabilities, and then for pulling down Automatic Dependent Surveillance–Broadcast (ADS-B) aircraft data and turning it into a sweeping radar visualization — bringing the circular display all the way back to its originally intended purpose, albeit being driven by very different hardware.

"I can't recommend this project to beginners," JC warns. "It involves high voltages that can KILL you. So I left the details of the schematics out for now. I had built the circuits before the schematics anyways and they require some tinkering to get them to work properly."

Those detail-light schematics are available as a KiCad project, along with the source code for the ADS-B sweeper, on JC's GitHub repository under the reciprocal GNU General Public License 3. More information can be found on the project's Hackaday.io page.