Ardusub Rc control 40MHz functionality

Our product owners want a backup rc system using a 40Mhz receiver with a custom made controller to function as a backup control system should the companion computer crash. this only needs to work close to water at less than 5m depth to return it to the surface and steer it back to the shore so it can be picked up.

To that end i want to know which files are entangled in the RC_Channel file as i can see that RC_Channel is also being used in Radio.cpp and Joystick.cpp but i cant find how the PPM channel in RCIN gets turned into the (8) channels and how i would re-implement said channels in the code.

Any info on how to do this would be of great help.

(PS: we know its not supported and not nearly the best solution but its the solution they want)

Hi @Sublink
I could be wrong, but I don’t believe ArduSub supports any form of RC radio use - even if a PPM signal was able to be sent at 40Mhz thru the water, it may not have the bandwidth and certainly would not penetrate 5m? It is possible to control ArduRover and the BlueBoat with a radio receiver that supports SBUS output - that’s the feature you should look for when hunting a 40Mhz receiver - if such a thing exists, than it may be possible to get it working with ArduSub.

It is very unusual for the companion computer to crash, especially if it is running BlueOS! Typically, retrieving a dead ROV is as easy as pulling on the tether connected to it, but if it is fouled up a better solution may be a second ROV with gripper bein used to retrieve the first? Assuming that a human wouldn’t be able to enter and solve the issue…

SBUS is also an options so if that works then that would be great but wont switching to ArduRover mean losing a lot of the built in sub functions?

They want a tetherless setup which will mostly do tasks autonomously but in case of failure (testing self made programs) they want the backup RC

(The setup for now is a Pixhawk 6C with probably a Pi5 as companion for the autonomous tasks)

They would prefer to keep the built in functions of ArduSub and that we rebuild the RC functionality but were having issues finding out how to actually build it back into ArduSub

Hi @Sublink -
You definitely want to use ArduSub not ArduRover, I was only mentioning as Rover has the necessary support for SBUS input with the Navigator. If you can actually find a receiver that supports SBUS at 40Mhz, and penetrates water with the signal, please share a link! I’m very skeptical that such a thing exists, but would love to be proven wrong.

We’re not sure if ArduSub would work with SBUS input, some functionality may exist such as basic movement, but things like changing modes are not supported (and likely critical)

I’d suggest keeping the tether, and removing for validation of autonomous use may be more reliable - perhaps an acoustic modem could be used as a fail-safe cut-off in this situation? In general, an acoustic modem may be better suited for your application…