Arduino field control for vex V5. fc contains a project that just uses the arduino serial library, and fc_wifi adds the AsyncMQTT library to connect to wifi & mqtt to get data(instead of just serial).
The field control sequence(aka when the controller sends 0xA7) can be responded to with either a 0x02 ACK packet to acknowledge that the current values are correct, or a 0x53 packet to send new values. However, a 0x02 must be sent at least every 20 packets else the controller will restart the connect sequence.
All of the protocol reversing has been done with 1 brain & 1 controller, so any unique fields are constant and will need to be updated.