Lesson 5 of 5

Wi-Fi web switch

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#include <WiFi.h> #include <WebServer.h> // The bench network: SSID and password const char* SSID = "bench-lab"; const char* PASSWORD = "robotics"; const int LED_PIN = 23; WebServer server(80); void handleOn() { digitalWrite(LED_PIN, HIGH); server.send(200, "text/plain", "LED on"); } void handleOff() { digitalWrite(LED_PIN, LOW); server.send(200, "text/plain", "LED off"); } void setup() { Serial.begin(115200); pinMode(LED_PIN, OUTPUT); WiFi.mode(WIFI_STA); WiFi.begin(SSID, PASSWORD); Serial.print("Connecting to "); Serial.println(SSID); while (WiFi.status() != WL_CONNECTED) { delay(250); Serial.print("."); } Serial.println(); Serial.print("Connected, IP address: "); Serial.println(WiFi.localIP()); // Each path runs its own handler server.on("/on", handleOn); server.on("/off", handleOff); server.begin(); } void loop() { server.handleClient(); }

Stopped · Your code isn't running yet. Until you press Run, the board runs the program already on it.

Nothing printed yet. Press Run.

Join the bench Wi-Fi network, start a small web server and switch the LED from a browser: /on and /off.

A real WebServer with two routes
Wi-Fi bursts can brown out a weak supply
Connection takes about a second, as on the bench

Pin	Connects to	What it does
`GPIO23`	220 Ω resistor, then the LED's anode	Output switched by the web server
`GND`	LED cathode	Return path

Wire it in

Sensors and actuators this board drives, with the real connections.

All 8 parts on the ESP32-DevKitC V4 page

Wi-Fi web switch

Try it yourself

Serial monitor

Checks

Break it

Inputs

Parameters

Wire it in

Wi-Fi web switch

Try it yourself

Serial monitor

Checks

Break it

Inputs

Parameters

Wire it in