ESP32 WIFI Lessons

Explore the ESP32 wifi flow in soft ap mode, from app core to lwIP and wifi driver, including ap start and event handling of station connections.

Learn the ESP32 wifi station mode workflow, initializing the wifi driver, configuring SSID and password, and handling wifi and IP events with an event group to report status.

Learn to implement a tcp client on the ESP32 with the lwIP tcp ip stack and BSD sockets API, including creating, connecting, sending, receiving, and closing sockets for server communication.

Learn how to build an ESP32 wifi tcp server using lwIP sockets, following the standard soc development flow, including socket init, listen, accept, receive, send, and close.

Compare UDP and TCP: UDP is connectionless, faster, and supports multicast, while TCP is reliable and connection-based, suitable for email, FTP, and HTTP.

Explore the ESP32 UDP client workflow, including configuring host IP and port, creating a socket, sending a payload to the UDP server, receiving responses, and reconnecting on reset.

Implement a udp server on the esp32 over wifi, using socket operations to bind, receive from, and send back data while displaying the client ip and port.

Learn the http protocol to build an ESP32 http server and enable browser control. Understand requests and responses, including request lines, headers, bodies, methods get and post, and status codes.

Demonstrates the http url structure, including protocol, user info, domain or ip, port, path, query string, and anchor, and shows how the browser uses urls to fetch pages.

Explore how to implement an ESP32 http get handler, parse request headers and url query strings, and return dynamic pages based on id and number parameters.

Learn how to perform http post on the ESP32 edge by submitting a form with name and age and handling the post response from the server.

Learn how to implement the http put method on the ESP32, sending data to a web server and processing responses with a put function, including testing via Chrome developer tools.

learn how to perform http requests on the esp32 to fetch data from a web server, build the http get request, and parse the http response for weather data.

learn how the websocket upgrade uses an http handshake and a 101 code to establish a persistent, two-way data stream for real-time communication.

Learn the WebSocket data frame format for ESP32, including the fin bit, opcode, masking, and payload length rules (0-125, 126, 127) for text and binary payloads.

Explain how the ESP32 WebSocket server performs the handshake, detects the protocol version, exchanges keys, and upgrades the connection, enabling the receive and send of data.

Learn how the webOS SOC server 02 processes received data from handshake to payload decoding, handling frame types (continue text, binary, ping pong) and unmasking into memory buffers.

Learn how the WebSocket server constructs and sends data frames, using http ws send frame async and a queue, then handles framing, payload length, and session sending.

Explore browser-based and ESP32 WebSocket clients that communicate with a server, including handshake, opening connections, sending data, and handling incoming messages.

Learn to extend the ESP32 http server into a websocket server that sends ten data frames to the client, with payload preparation, frame configuration, and debugging via browser websocket tools.

Discover how the ESP32 websocket client reads server data by running the webOS client on the device, exploring the workflow, event handling (connected, data, error), and timer usage.

Explore how a websocket client uses timers and semaphores to manage data transmission, timeouts, and graceful shutdown in an ESP32 workflow.

Explore MQTT, a lightweight IoT protocol for publish/subscribe messaging, using topics to move sensor data between devices and servers with quality of service levels 0 to 2, persistence, and security.

Explain the MQTT protocol structure, including the fixed header, variable header, and payload, and illustrate how connect packets carry username, password, and a client identifier in version five.

Implement an ESP32 MQTT client that publishes data to a server every 5 seconds and subscribes to the same topic, with MQTT event handling and a timer callback.

Explore the eclipse mosquitto mqtt server for esp32 projects, highlighting its open source, lightweight design, and mqtt protocol support, with testing on a public online server.

Explore ESP now, a connectionless wifi protocol that merges the first five tcp/ip layers into one, reducing code, cpu usage, and power while enabling 500 meters unicast, multicast, and broadcast.

Explore the ESP Now data frame format for ESP32, covering the mac header, frame body with category code and vendor-specific fields, and the frame control with a 250-byte payload.

Learn how to obtain the ESP32 base MAC address for ESP-NOW communication and how to read MAC addresses for wifi station, Bluetooth, and soft AP using the IDF SDK.

Initialize ESP now on the ESP32, add a paired device, and prepare to send data with a target MAC address. Monitor send status via callbacks and respect the 250-byte limit.

Implement the ESPNow receive data flow on the ESP32 by adding the receive data function, setting up the receive callback, printing received data, and compiling and flashing the board.

Shows how to implement ESP-NOW broadcast on ESP32 by using the broadcast MAC address, sending a hello buffer to multiple devices, and validating with monitor outputs.