Radio Master TX16S Setup

In v2.0x, HeadTracker supports SBUS output by default on pin P1.03. It is activated always, thus there is no GUI checkbox to activate it. In case you need an inverted SBUS signal, attach to pin P1.10 instead

HeadTracker Version 2.1x SBUS output is always on pin P1.03 (TX). There is now an option in the GUI to invert the signal if needed. https://headtracker.gitbook.io/head-tracker/settings/gui-settings/output#serial-bus-sbus. You will need to choose inverted for the TX16s. You can also adjust the update rate in the GUI to whatever you desire in the newer version. * If your using it on a receiver board (Option 3) I would suggest 80Hz. to match the Bluetooth update rate. P1.10 is reserved for SBUS input in a future update.

Wiring

You can connect your HeadTracker based on Arduino Nano 33 BLE / BLE Sense to TX16S AUX1 or AUX2 port as follows:

Connections (AUX1 or AUX2)

• GND to GND

• VIN to 5V pin, and

• TX of Nano P1.03 (=non-inverted SBUS output) to RX of TX16S

TX16S AUX TX remains unconnected. The Arduino Nano 33 BLE / BLE Sense gets powered via RadioMaster TX16S AUX port, no extra power is required.

SBUS Trainer via the bottom UART ports requires Open TX version 2.3.10 or newer. EdgeTX is supported from 2.4 and up

If you have a Open/Edge TX firmware with Bluetooth you will only see one Serial Port listed. This is AUX1 port (Left one in above photo). Bluetooth uses AUX2 in this case (The right one)

Head Tracker GUI Settings

In the GUI the inverted option needs to be selected. SBUS uses a idle signal level which is low. Radio Master expects a standard UART signal, which is idle high.

If you are running a direct wired connection to the AUX port you can increase the Update Rate to the full 150Hz. If you are using this in wireless mode (Option 3) Choose 80Hz, which will match the Bluetooth update rate.

Settings in EdgeTX/OpenTX

• set SYSTEM -> HARDWARE -> Serial port to SBUS Trainer (left image shows EdgeTX, right image OpenTX):

Please note that OpenTX (up to v2.3.12) erroneously lists TTL for serial ports - TX16S uses 3.3V logic levels!

• In MODEL -> MODEL SETUP -> Trainer, set Mode to Master/Serial

• For testing purposes, the next example enables all 16 SBUS channels from HeadTracker. Lets create for this under MODEL -> SPECIAL FUNCTIONS a special function Trainer with value Chans and lets enable it (tick the checkbox). The following example uses switch C position up for overriding all 16 SBUS channels with data from HeadTracker:

In a permanent setup, you most likely only want to override a few specific channels from HeadTracker - for this, skip the special function and choose TR(x) in mixes page on the specific channels you want to include, instead.

Verifying the operation

• To verify that all works as expected, select from main menu (long roller press) Channel Monitor (EdgeTX) or Monitors (OpenTX):

• Check the channel values in the channel monitor. Flipping switch C up, should show the HeadTracker channels in the upper bars of each channel (the examples here show a signal for only the first 3 channels):