Setup Receiver - rotorflight/rotorflight GitHub Wiki

One of the first things you should do is connect a receiver to the FC. Your FC has several UARTs, and each UART has an RX and a TX. A receiver needs to be connected to an RX and/or TX pad, depending on the kind of receiver.

  • DSM2/DMSX/IBUS/TBS need to be connected to a free UART RX.
  • SBUS also needs to be connected to an RX pad. However, it's an inverted signal, so set serialrx_inverted = ON if you have an F7 processor. If you're using an F4, use the SBUS pad and read this.
  • FPort can be connected to a TX pad. It's also an inverted signal.
  • ELRS needs an RX and a TX on the same UART.
  • SBUS with SmartPort needs to be connected to a free UART RX and a TX of another free UART. Both signals are inverted.

Please see the documentation for your FC for more details on how to connect your receiver.

Receiver tab

Configure your receiver

Connect the FC to your computer and go to the Receiver tab in Rotorflight Configurator to configure your receiver.

  • Check Channel Map and make sure the Receiver Channels respond as expected.
  • Revert channels on your transmitter if a channel responds the wrong way around.
  • Make sure that centre stick is at 1500µs. You might need to recalibrate your transmitter now and then.
  • Set channel endpoints to 1000µs and 2000µs.
  • Do not use trim for Roll, Pitch or Yaw on your transmitter.
  • You can use trim for Collective to adjust zero collective pitch.

You should end up with something like this:

Receiver tab

Deadband

Set RC deadband and Yaw deadband to the smallest possible value that doesn't make your model drift in the preview window.

OpenTX / EdgeTX

The channel mid- and endpoints can be set on the Output page of your model.

  • Set Min so that full left/down stick indicates 1000µs (e.g. -97.8).
  • Set Max so that full right/up shows 2000µs.
  • Set PPM Center to 1500.

But... my transmitter can't set endpoints!

Some old transmitters can't adjust endpoints. In that case you could use the rxrange CLI command to scale the output of your transmitter to 1000-2000µs. Oscar can show you how.

I'm only using RX2 for my receiver. Can I use TX2 for something else?

No. You can't connect two different devices to the same UART. So you can't connect an SBUS receiver to RX2 and OpenLager to TX2, for example.

Calibrating Stability Mode

The stability modes (Angle, Horizon or Rescue) can be calibrated so that the heli doesn't drift much when using such a mode. This can only be done via the accelerometer trims. Do not use trim on your transmitter.