# S.BUS Conversion for Sentinel

Source: https://forum.modalai.com/topic/3128/s-bus-conversion-for-sentinel
Category: Development Drones (https://forum.modalai.com/category/44/development-drones)
Tags: sentinel
Posted: 2024-02-18 17:01:59 UTC by JoeC
Replies: 4 · Views: 1311

## JoeC · 2024-02-18 17:01:59 UTC

Hello, I'm trying to retrofit an early Sentinel design with an S.BUS receiver. The Sentinel has been upgraded to the most recent SDK 1.1.3.  In this model, J18 is taken by the VOXL ESC board.  A Spektrum receiver cable is split between J10 and J19 and going to the older Sentinel Spektrum bind board.  If I could utilize the J19 as an S.BUS input, that might be the way to go?  I'm not sure how to ensure the PX4 stack is looking for the RC S.BUS signal on J19 rather than J18 like usual.  Any thoughts appreciated, thanks!

-Joe

## Reply by Eric Katzfey (ModalAI staff) · 2024-02-20 16:25:10 UTC

@JoeC The Voxl2 does not support sbus. You would need an adapter board such as https://www.modalai.com/products/voxl2-io?variant=40610514206771

## Reply by JoeC · 2024-02-24 00:13:19 UTC (in reply to Eric Katzfey)

@Eric-Katzfey Thanks Eric, Apologies, I needed to also indicate that I've got a VOXL2 IO board in this as well.  Hence, I should ask,  "Can J19 be used as a UART that goes to a VOXL2 IO board?"

-Joe

## Reply by Eric Katzfey (ModalAI staff) · 2024-02-25 17:48:10 UTC (in reply to JoeC)

@JoeC What does your `/etc/modalai/voxl-px4.conf` file look like? For your desired configuration you should set `RC=M0065_SBUS` and `ESC=VOXL_ESC`.

## Reply by JoeC · 2024-03-02 20:52:53 UTC (in reply to Eric Katzfey)

@Eric-Katzfey Thanks for your help.  I've confirmed that I was able to use J19 with the "RC=M0065_SBUS" option successfully.  Hence, if no VOXL_ESC, one should use J18 for the VOXL2 IO board and if there IS a VOXL_ESC board, one should use the J19 for the VOXL2 IO board.  The firmware seems to be "smart" enough to figure out as long as /etc/modalai/voxl-px4.conf is set as you suggested.

-Joe