ESP32 - WIFI SCAN

ESP32 WiFi Scan Example

Introduction

ESP32 Wi-Fi Modes -

The ESP32 board can act as Wi-Fi Station, Access Point or both. To set the Wi-Fi mode, use WiFi.mode() and set the desired mode as argument:

WiFi.mode(WIFI_STA) - station mode: the ESP32 connects to an access point

WiFi.mode(WIFI_AP) - access point mode: stations can connect to the ESP32

WiFi.mode(WIFI_AP_STA) - access point and a station connected to another access point

Wi-Fi Station -

When the ESP32 is set as a Wi-Fi station, it can connect to other networks (like your router). Your can connect to ESP using the IP address assigned by router.

Access Point -

When you set your ESP32 board as an access point, it creates its own Wi-Fi network and you can be connect any device with Wi-Fi capabilities to your ESP32 board.

Wi-Fi Station + Access Point -

The ESP32 can be set as a Wi-Fi station and access point simultaneously.

Scan Wi-Fi Networks -

The ESP32 can scan nearby Wi-Fi networks within its Wi-Fi range.

Step 1: Connect Board to Laptop

Step 2: Scan Wi-Fi Networks Example Code

Select boar ESP32 DEV Module from Tools >> Boards menu, then select appropriate com port. Upload this program to ESP32.

#include "WiFi.h"

void setup()

{

Serial.begin(115200);

// First, set the Wi-Fi mode. If the ESP32 connected to another network (access point/hotspot) it must be in station mode.

WiFi.mode(WIFI_STA);

WiFi.disconnect();

delay(100);

Serial.println("Setup done");

}

void loop()

{

Serial.println("Scan start");

// WiFi.scanNetworks will return the number of networks found.

int n = WiFi.scanNetworks();

Serial.println("Scan done");

if (n == 0) {

Serial.println("no networks found");

} else {

Serial.print(n);

Serial.println(" networks found");

Serial.println("Nr | SSID | RSSI | CH | Encryption");

for (int i = 0; i < n; ++i) {

// Print SSID and RSSI for each network found

Serial.printf("%2d",i + 1);

Serial.print(" | ");

Serial.printf("%-32.32s", WiFi.SSID(i).c_str());

Serial.print(" | ");

Serial.printf("%4ld", WiFi.RSSI(i));

Serial.print(" | ");

Serial.printf("%2ld", WiFi.channel(i));

Serial.print(" | ");

switch (WiFi.encryptionType(i))

{

case WIFI_AUTH_OPEN:

Serial.print("open");

break;

case WIFI_AUTH_WEP:

Serial.print("WEP");

break;

case WIFI_AUTH_WPA_PSK:

Serial.print("WPA");

break;

case WIFI_AUTH_WPA2_PSK:

Serial.print("WPA2");

break;

case WIFI_AUTH_WPA_WPA2_PSK:

Serial.print("WPA+WPA2");

break;

case WIFI_AUTH_WPA2_ENTERPRISE:

Serial.print("WPA2-EAP");

break;

case WIFI_AUTH_WPA3_PSK:

Serial.print("WPA3");

break;

case WIFI_AUTH_WPA2_WPA3_PSK:

Serial.print("WPA2+WPA3");

break;

case WIFI_AUTH_WAPI_PSK:

Serial.print("WAPI");

break;

default:

Serial.print("unknown");

}

Serial.println();

delay(10);

}

Serial.println("");

// Delete the scan result to free memory for code below.

WiFi.scanDelete();

// Wait a bit before scanning again.

delay(5000);

}

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