Questions about P2P communication in crazyflies

[erestrep]

Last week at ICRA 2026 in Vienna I discussed with Stefan Thorstenson who told me there was P2P communication between the crazyflies implemented in the demo at the bitcraze booth. He suggested me to start a discussion about it to get some info. Working on multi-robot research myself, this is something that could directly impact the experimental tests of my research, so I got very excited about it and I have some general questions:

1. If I understood well, this P2P link direct between robots, that is, it is done without passing through the radio, it that true?
2. In any case how is this communication setup, is it done using ESP Now?
3. If it's based on ESP now, could one setup a P2P link with other ESP-based devices?
4. Does it only work if the drones have on-board computation (e.g., with the AI deck)?

In general I would very much appreciate any information you could give me about this.

In any case, thanks a lot Stefan for reaching out and all the team for your work!

[ArisMorgens]

Hello @erestrep!

Thanks for passing by the booth! I'll try to answer your questions and maybe @ataffanel wants to add something more later.

If I understood well, this P2P link direct between robots, that is, it is done without passing through the radio, it that true?

Yes, the P2P packets go straight to the Crazyflie's onboard nRF51 chip. Each drone broadcasts a packet and every other drone in the same radio channel receives it. No Crazyradio dongle is needed. In the decentralized demo that you saw at ICRA, we use a Crazyradio as a "sniffer", collecting all the packets broadcasted by the Crazyflies and creating a visualization.

In any case how is this communication setup, is it done using ESP Now?

The Crazyflie's P2P protocol is running on Nordic's nRF51 chip. You find the firmware we're using for it here.

Does it only work if the drones have on-board computation (e.g., with the AI deck)?

No. The P2P broadcast runs entirely on the Crazyflie's main STM32 and nRF51 chips.

If you're interested in learning more about it, we have some minimal examples of P2P communication in the main crazyflie-firmware repository.

Let us know if you have any other questions.

[erestrep]

Thanks a lot for the reply. It is really helpful, I will check the info on the firmware as you suggest!