How does smartphones communicate with controlled devices?
When using Wi-Fi wireless transmission media, a smartphone can communicate with the controlled device through TCP/IP protocol or UDP protocol after obtaining the IP address of the controlled device. Generally speaking, as the receiver, the controlled device receives control commands sent by the smartphone in local control; and the smartphone,as the sender, sends control commands to the controlled device. Therefore, the controlled device plays the role of a server; and the smartphone plays the role of a client, allowing multiple clients to send control commands to the server. This part will be introduced in detail in section 8.3.