SmartAudio or Tramp are communication protocols between the flight controller and the video transmitter hardware of a RC drone or model aircraft.
Through these protocols, the flight controller is able to adjust the video transmitter settings. The adjustments are the power, the band and the channel of the transmission.
SmartAudio is a protocol created by TBS (Team Blacksheep) for it’s brand video transmitters. Tramp is a protocol created by ImmersionRC for the Tramp HV video transmitter. Nowadays both protocols are used in several other video transmitters. An example is the RUSH TANK VTX, which uses the SmartAudio protocol, or the Matek VTX, which uses the IRC Tramp protocol.
A VTX capable of communicating with the controller can be comfigured via the OSD menu or the radio control screen so that it makes choosing the channel, the band and the transmission power simpler without having to press buttons. This allows you to install the VTX in hard-to-reach spaces without this making difficulty to make these adjustments.
It also allows the flight controller to manage the VTX. For example: You can program the VTX to transmit at its maximum power when the airplane is farther away, and reduce the transmission power when it is closer so as to reduce interference in the video of other pilots. Or make the drone transmit video only when it is armed, and when it is disarmed, make the VTX goes into “Pit-mode” (without transmitting anything).
Both protocols are bidirectional and use only a single wire for communication, so the communication is half-duplex. The controller can send commands to the VTX, and also receive VTX information over the same wire.
Every video transmitter (VTX) compatible with one of these protocols has a dedicated wire for communication with the controller. This wire must be connected to a TX pin of any free UART on the flight controller, or to a SoftSerial pin.
Currently the SmartAudio and Tramp protocols are supported by the following flight control systems:
BetaFlight, CleanFlight, Inav, KISS, dRonim, FlightOne, ButterFlight
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