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The huVVer-AVI™ is a general-purpose customizable aircraft instrument series that uses the Espressif Systems ESP-32 microprocessor.

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huVVer AVI (2.25″ Instrument Cutout)

In this particular article we will discuss the huVVer AVI TBX uAvionix tailBeaconX™ Transponder Controller and the capabilities it brings being implemented in a experimental aircraft.

Using the standard huVVer-AVI™ instrument hardware baseline, the device is preloaded with the huVVer-AVI™ Transponder Controller (TBX) firmware and connects between a compatible serial altitude encoder and a tailBeaconX™ Mode-S/ES diversity transponder. It relays the altitude information from the encoder (or a compatible EFIS device or encoding altimeter) and provides the ability to enter Squawk codes, control the transponder Modes, and provide diagnostic information.

Created for experimental aircraft applications, the huVVer-AVI Transponder Controller provides a bright 2.4 inch (61 mm) LCD screen, dual RS-232 serial ports, a sensor input for an optional external IDENT switch, and four front-panel pushbuttons. Versions are available for either 2.25” or 3.125” standard aircraft panel cutout sizes. Both 14V and 28V electrical systems are supported.


  • Provides a complete control head for the uAvionix tailBeaconX™ diversity transponder.
  • Works with existing serial altitude encoders, Electronics Flight Instrument Systems (EFIS), or encoding altimeters.
  • Supports an optional external IDENT button.
  • Software App updatable using WiFi for Over-The-Air (OTA) software upgrades.
  • Daylight Readable 850 cd/m2 320 x 240 pixel US-made color display.
  • Operates from 8 to 35 Volts DC with -20 °C to +55 °C ambient temperatures and provides extensive power and I/O conditioning to increase reliability in harsh environments.


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