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communication between two CF2.0

Posted: Tue Sep 12, 2017 11:48 am
by cha8138
Hello!
I am kind of stuck doing my undergraduate project, because I am not sure how to make crazyflies to communicate each other.

1. Is there any way to send log data from a CF 2.0(A) to a CF2.0 (B)? If possible, please let me know...
2. If there is no way to send log data from CF 2.0 to CF 2.0, I think the only way to send log data is to use crazyradio and python library.
If so, I wonder if there is any code or project I can refer to.
3. Anyone who have possible better ideas on this problem, please give me some advice...

Thank You :D

Re: communication between two CF2.0

Posted: Tue Sep 12, 2017 12:36 pm
by arnaud
Hi,

1. Peer-to-peer communication is not possible with the current code but possible in hardware, it is all open source and the radio chip is well documented.
2. You can look at the python lib examples. There is examples to log data, set parameters and connect multiple Crazyflies. It seems that what you need is a combination of the 3: https://github.com/bitcraze/crazyflie-l ... r/examples.
3. If you do not want to add a new radio, peer to peer communication or communicating through the computer using Crazyradio or other nRF51-compatible radio seems like your two main options.

For peer-to-peer communication you would have to enhance the radio implementation to allow Crazyflie to send packets (currently it only answers with ack packet) and then implement a new protocol to allow the STM32 to send packets to the other CF2.

What kind of data do you want to transmit between the CF2s?

Re: communication between two CF2.0

Posted: Wed Sep 13, 2017 7:59 am
by cha8138
Thank you!!

I want to log GPS data which is consisted of various data types and transmit the data to the other CF 2.0.

Can I ask one more?
Will it be possible to transmit more than 50 variables (GPS data) through peer-to-peer communication?

Re: communication between two CF2.0

Posted: Wed Sep 13, 2017 8:21 am
by arnaud
It depends of the size and how often you want to send the data.

The radio link has a datarate of 2Mbit/s and when communicating with the Crazyradio it is limited to 32Bytes packets so you will most likely need to break-up the communication in multiple packets.

The 32bytes packet limitation is a limitation of the Crazyradio though. The nRF51 radio chip contained in the Crazyflie can send and receive bigger packet, so when communicating peer to peer you might be able to send all your data at once (again, it depends of the size of your variables ....).