Function for this platform

Also see:https://www.yuque.com/books/share/6ad4406d-981b-4fd7-b14e-2bd05bdc92dd?# 《Raybot机器人控制平台》

Raybot program on board

server.py

Main program.
- control command data transmission by:
  - tcp_server(): TCP/IP server
  - UART(via LFC chip)
- Visual Servo module
  - zmq server
- sensor data collector
MotorDriver.py
PCA9685.py
RayPID.py
RayADRC.py

Android client

client_tkinter.py

need Pydroid 3 to run.
- UI
- TCP/IP client (send command)
- zmq client (receive video stream)
- UART writer/reader

SBE client

client_tkinter_SBE.py
work as a Low frequency remote control.
- UI
- UART writer