nRF5x as a RC receiver with RC transmitter

[Luis]

Hello, Can I use nRF5x to receive packets/info sent from a "standard" radio control transmitter?

Like the ones used to fly RC planes and copters.

Extra details

I own these rc transmitters:

Turnigy 9X

Turnigy 5X

They use 2.4GHz, FHSS, and no idea about what protocol.

Is there any way I can program my nRF5x devices to act as receivers with these transmitters directly? So they can be paired and used directly instead of having to use their original receivers.

I have searched the web but did not find anything useful.

Maybe implementing a new propietary protocol? Or is there any hardware reason this cannot work?

I really appreciate any hints on this, wether you think it is possible or not, why, or if you could point me to any related project. Thanks a lot,

Luis Rodenas

[Anders Strand]

Hello.

Without knowing the radio protocol spec of the transmitter, this is virtually impossible. Things that would have to match is: Data rate, packet structure, modulation method, frequency deviation and channel spacing.

You can extract this information by looking at the signal from a transmitter using an advanced frequency analyzer. You could also ask Turnigy if they want to share the protocol with you.

You can read about the radio in the nRF5 devices here. It uses GSFK modulation, and can use up to 2mpbs data rate.

If your goal is to connect a transmitter to an nRF5 in any way, you can always get a very small receiver and read the PWM output with the nRF5 chip.

According to this thread, some Turnigy devices use an A7121 tranceiver chip. You might have better luck using one of these chips, then you are left with decoding the packets that come in. This might also be a big task :)

-Anders

[Luis]

Great answer. Thanks for pointing out difficulties and showing me that thread with useful info. Right now I am reading PWMs from receiver, just wanted to try to simplify it. Adding a new transceiver chip is not an option right now, that is what you suggested about A7121 right? I will ask turnigy about their protocol, but I am pretty sure they wont share it due to safety reasons. Because knowing protocol I could maybe hack other communications, is it like this? Thank you again