Introduction
Welcome, tech enthusiasts, to an exciting journey through the realm of ESP32 WiFi connectivity! In this comprehensive guide, we’ll unravel the magic behind ESP32’s WiFi capabilities, exploring both Station (STA) and Access Point (AP modes). Whether you’re an aspiring developer or a curious mind looking to conquer the world of IoT, this blog post is your gateway to mastering ESP32 WiFi connectivity.
We’ll delve into the intricacies of configuring WiFi settings using the “menuconfig” utility, provide clear explanations, and equip you with complete code examples to ensure you become an ESP32 WiFi maestro. So, let’s dive in and harness the power of ESP32 to create seamless and versatile WiFi-enabled projects!
What is ESP32 and Why WiFi Matters
Before we embark on our journey, let’s briefly introduce the ESP32. It’s a versatile microcontroller that combines power and efficiency, making it an ideal choice for a wide range of IoT applications. One of its standout features is its built-in WiFi connectivity, which allows you to connect to the internet or create your own local networks.
Why WiFi Matters
WiFi connectivity in ESP32 opens up a world of possibilities. You can build IoT devices that collect data, communicate with other devices, or even control appliances remotely. To harness this potential, understanding how to configure ESP32 WiFi settings is essential.
Exploring Station Mode
What is Station Mode?
Station mode (STA) enables your ESP32 to connect to an existing WiFi network, just like your smartphone or laptop. This mode is perfect when you want your ESP32 to access the internet or communicate with other devices on the same network.
Use Case: STA mode is used when you want your device to join an existing WiFi network to access the internet or communicate with other devices on the same network. For example, your smartphone uses STA mode to connect to your home WiFi.
Menuconfig for STA Mode
The first step to configuring WiFi settings is using the “menuconfig” utility. We’ll walk you through it step by step.
- Access the Menuconfig: Open your ESP32 project in the terminal and run the following command:
make menuconfig- Navigate to WiFi Settings: Use the arrow keys to navigate to “Component config” -> “ESP32-specific” -> “WiFi.” Here, you can set your WiFi SSID and password.
- Configure WiFi SSID and Password: Enter the SSID (WiFi network name) and password when prompted. This information allows your ESP32 to connect to the network.
- Save Configuration: Save the configuration and exit the menuconfig utility.
Code Implementation
Now that you’ve configured your WiFi settings, let’s dive into the code.
Here’s a simple example of how to use STA mode to connect to a WiFi network:
#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_wifi.h"
#include "esp_event.h"
#include "esp_log.h"
#define WIFI_SSID "YourWiFiSSID"
#define WIFI_PASS "YourWiFiPassword"
void wifi_init_sta() {
wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
esp_wifi_init(&cfg);
wifi_config_t wifi_config = {
.sta = {
.ssid = WIFI_SSID,
.password = WIFI_PASS
},
};
esp_wifi_set_mode(WIFI_MODE_STA);
esp_wifi_set_config(ESP_IF_WIFI_STA, &wifi_config);
esp_wifi_start();
}
void app_main() {
esp_log_level_set("wifi", ESP_LOG_NONE);
ESP_ERROR_CHECK(esp_event_loop_create_default());
wifi_init_sta();
}This code initializes WiFi in STA mode, sets the SSID and password you configured using “menuconfig,” and establishes a connection to the network.
Discovering Access Point Mode
What is Access Point (AP Mode)?
Access Point mode (AP mode) transforms your ESP32 into a WiFi hotspot. This means other devices can connect to your ESP32, creating a local network. AP mode is invaluable for projects that require devices to communicate with your ESP32 directly.
Use Case: AP mode is useful when you want to create your own local network where other devices can connect directly to your device. This is handy for IoT projects, where you might have sensors or smart devices connecting to a central controller (e.g., an ESP32) in AP mode.
Menuconfig for AP Mode
Configuring AP mode in “menuconfig” is as straightforward as Station mode:
- Access the Menuconfig: Run
make menuconfigin your ESP32 project’s terminal. - Navigate to WiFi Settings: Go to “Component config” -> “ESP32-specific” -> “WiFi” and select “Access Point (AP mode) Configuration.”
- Configure AP Settings: Enter the SSID and password you want for your ESP32’s hotspot. You can also set the maximum number of connections.
- Save Configuration: Save and exit the menuconfig utility.
Code Implementation for AP Mode
Now, let’s put your ESP32 in AP mode with this simple code example:
#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_wifi.h"
#include "esp_event.h"
#include "esp_log.h"
#define AP_SSID "MyESP32AP"
#define AP_PASS "MyESP32Password"
void wifi_init_softap() {
wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
esp_wifi_init(&cfg);
wifi_config_t wifi_config = {
.ap = {
.ssid = AP_SSID,
.password = AP_PASS,
.max_connection = 4, // Set maximum allowed connections
.authmode = WIFI_AUTH_WPA_WPA2_PSK
},
};
esp_wifi_set_mode(WIFI_MODE_AP);
esp_wifi_set_config(ESP_IF_WIFI_AP, &wifi_config);
esp_wifi_start();
}
void app_main() {
esp_log_level_set("wifi", ESP_LOG_NONE);
ESP_ERROR_CHECK(esp_event_loop_create_default());
wifi_init_softap();
}This code initializes WiFi in AP mode, sets the SSID and password for your ESP32’s hotspot, and defines the maximum allowed connections and check the ESP32 connection in AP mode.
ESP32 in Both STA and AP Mode
/*
* SPDX-FileCopyrightText: 2023 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Unlicense OR CC0-1.0
*/
/* WiFi softAP & station Example
This example code is in the Public Domain (or CC0 licensed, at your option.)
Unless required by applicable law or agreed to in writing, this
software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
CONDITIONS OF ANY KIND, either express or implied.
*/
#include <string.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/event_groups.h"
#include "esp_mac.h"
#include "esp_wifi.h"
#include "esp_event.h"
#include "esp_log.h"
#include "esp_netif_net_stack.h"
#include "esp_netif.h"
#include "nvs_flash.h"
#include "lwip/inet.h"
#include "lwip/netdb.h"
#include "lwip/sockets.h"
#if IP_NAPT
#include "lwip/lwip_napt.h"
#endif
#include "lwip/err.h"
#include "lwip/sys.h"
/* The examples use WiFi configuration that you can set via project configuration menu.
If you'd rather not, just change the below entries to strings with
the config you want - ie #define EXAMPLE_ESP_WIFI_STA_SSID "mywifissid"
*/
/* STA Configuration */
#define EXAMPLE_ESP_WIFI_STA_SSID CONFIG_ESP_WIFI_REMOTE_AP_SSID
#define EXAMPLE_ESP_WIFI_STA_PASSWD CONFIG_ESP_WIFI_REMOTE_AP_PASSWORD
#define EXAMPLE_ESP_MAXIMUM_RETRY CONFIG_ESP_MAXIMUM_STA_RETRY
#if CONFIG_ESP_WIFI_AUTH_OPEN
#define ESP_WIFI_SCAN_AUTH_MODE_THRESHOLD WIFI_AUTH_OPEN
#elif CONFIG_ESP_WIFI_AUTH_WEP
#define ESP_WIFI_SCAN_AUTH_MODE_THRESHOLD WIFI_AUTH_WEP
#elif CONFIG_ESP_WIFI_AUTH_WPA_PSK
#define ESP_WIFI_SCAN_AUTH_MODE_THRESHOLD WIFI_AUTH_WPA_PSK
#elif CONFIG_ESP_WIFI_AUTH_WPA2_PSK
#define ESP_WIFI_SCAN_AUTH_MODE_THRESHOLD WIFI_AUTH_WPA2_PSK
#elif CONFIG_ESP_WIFI_AUTH_WPA_WPA2_PSK
#define ESP_WIFI_SCAN_AUTH_MODE_THRESHOLD WIFI_AUTH_WPA_WPA2_PSK
#elif CONFIG_ESP_WIFI_AUTH_WPA3_PSK
#define ESP_WIFI_SCAN_AUTH_MODE_THRESHOLD WIFI_AUTH_WPA3_PSK
#elif CONFIG_ESP_WIFI_AUTH_WPA2_WPA3_PSK
#define ESP_WIFI_SCAN_AUTH_MODE_THRESHOLD WIFI_AUTH_WPA2_WPA3_PSK
#elif CONFIG_ESP_WIFI_AUTH_WAPI_PSK
#define ESP_WIFI_SCAN_AUTH_MODE_THRESHOLD WIFI_AUTH_WAPI_PSK
#endif
/* AP Configuration */
#define EXAMPLE_ESP_WIFI_AP_SSID CONFIG_ESP_WIFI_AP_SSID
#define EXAMPLE_ESP_WIFI_AP_PASSWD CONFIG_ESP_WIFI_AP_PASSWORD
#define EXAMPLE_ESP_WIFI_CHANNEL CONFIG_ESP_WIFI_AP_CHANNEL
#define EXAMPLE_MAX_STA_CONN CONFIG_ESP_MAX_STA_CONN_AP
/* The event group allows multiple bits for each event, but we only care about two events:
* - we are connected to the AP with an IP
* - we failed to connect after the maximum amount of retries */
#define WIFI_CONNECTED_BIT BIT0
#define WIFI_FAIL_BIT BIT1
static const char *TAG_AP = "WiFi SoftAP mode";
static const char *TAG_STA = "WiFi Sta mode";
static int s_retry_num = 0;
/* FreeRTOS event group to signal when we are connected/disconnected */
static EventGroupHandle_t s_wifi_event_group;
static void wifi_event_handler(void *arg, esp_event_base_t event_base,
int32_t event_id, void *event_data)
{
if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_AP_STACONNECTED) {
wifi_event_ap_staconnected_t *event = (wifi_event_ap_staconnected_t *) event_data;
ESP_LOGI(TAG_AP, "Station "MACSTR" joined, AID=%d",
MAC2STR(event->mac), event->aid);
} else if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_AP_STADISCONNECTED) {
wifi_event_ap_stadisconnected_t *event = (wifi_event_ap_stadisconnected_t *) event_data;
ESP_LOGI(TAG_AP, "Station "MACSTR" left, AID=%d",
MAC2STR(event->mac), event->aid);
} else if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_START) {
esp_wifi_connect();
ESP_LOGI(TAG_STA, "Station started");
} else if (event_base == IP_EVENT && event_id == IP_EVENT_STA_GOT_IP) {
ip_event_got_ip_t *event = (ip_event_got_ip_t *) event_data;
ESP_LOGI(TAG_STA, "Got IP:" IPSTR, IP2STR(&event->ip_info.ip));
s_retry_num = 0;
xEventGroupSetBits(s_wifi_event_group, WIFI_CONNECTED_BIT);
}
}
/* Initialize soft AP */
esp_netif_t *wifi_init_softap(void)
{
esp_netif_t *esp_netif_ap = esp_netif_create_default_wifi_ap();
wifi_config_t wifi_ap_config = {
.ap = {
.ssid = EXAMPLE_ESP_WIFI_AP_SSID,
.ssid_len = strlen(EXAMPLE_ESP_WIFI_AP_SSID),
.channel = EXAMPLE_ESP_WIFI_CHANNEL,
.password = EXAMPLE_ESP_WIFI_AP_PASSWD,
.max_connection = EXAMPLE_MAX_STA_CONN,
.authmode = WIFI_AUTH_WPA2_PSK,
.pmf_cfg = {
.required = false,
},
},
};
if (strlen(EXAMPLE_ESP_WIFI_AP_PASSWD) == 0) {
wifi_ap_config.ap.authmode = WIFI_AUTH_OPEN;
}
ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_AP, &wifi_ap_config));
ESP_LOGI(TAG_AP, "wifi_init_softap finished. SSID:%s password:%s channel:%d",
EXAMPLE_ESP_WIFI_AP_SSID, EXAMPLE_ESP_WIFI_AP_PASSWD, EXAMPLE_ESP_WIFI_CHANNEL);
return esp_netif_ap;
}
/* Initialize wifi station */
esp_netif_t *wifi_init_sta(void)
{
esp_netif_t *esp_netif_sta = esp_netif_create_default_wifi_sta();
wifi_config_t wifi_sta_config = {
.sta = {
.ssid = EXAMPLE_ESP_WIFI_STA_SSID,
.password = EXAMPLE_ESP_WIFI_STA_PASSWD,
.scan_method = WIFI_ALL_CHANNEL_SCAN,
.failure_retry_cnt = EXAMPLE_ESP_MAXIMUM_RETRY,
/* Authmode threshold resets to WPA2 as default if password matches WPA2 standards (pasword len => 8).
* If you want to connect the device to deprecated WEP/WPA networks, Please set the threshold value
* to WIFI_AUTH_WEP/WIFI_AUTH_WPA_PSK and set the password with length and format matching to
* WIFI_AUTH_WEP/WIFI_AUTH_WPA_PSK standards.
*/
.threshold.authmode = ESP_WIFI_SCAN_AUTH_MODE_THRESHOLD,
.sae_pwe_h2e = WPA3_SAE_PWE_BOTH,
},
};
ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_STA, &wifi_sta_config) );
ESP_LOGI(TAG_STA, "wifi_init_sta finished.");
return esp_netif_sta;
}
void app_main(void)
{
ESP_ERROR_CHECK(esp_netif_init());
ESP_ERROR_CHECK(esp_event_loop_create_default());
//Initialize NVS
esp_err_t ret = nvs_flash_init();
if (ret == ESP_ERR_NVS_NO_FREE_PAGES || ret == ESP_ERR_NVS_NEW_VERSION_FOUND) {
ESP_ERROR_CHECK(nvs_flash_erase());
ret = nvs_flash_init();
}
ESP_ERROR_CHECK(ret);
/* Initialize event group */
s_wifi_event_group = xEventGroupCreate();
/* Register Event handler */
ESP_ERROR_CHECK(esp_event_handler_instance_register(WIFI_EVENT,
ESP_EVENT_ANY_ID,
&wifi_event_handler,
NULL,
NULL));
ESP_ERROR_CHECK(esp_event_handler_instance_register(IP_EVENT,
IP_EVENT_STA_GOT_IP,
&wifi_event_handler,
NULL,
NULL));
/*Initialize WiFi */
wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
ESP_ERROR_CHECK(esp_wifi_init(&cfg));
ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_APSTA));
/* Initialize AP */
ESP_LOGI(TAG_AP, "ESP_WIFI_MODE_AP");
esp_netif_t *esp_netif_ap = wifi_init_softap();
/* Initialize STA */
ESP_LOGI(TAG_STA, "ESP_WIFI_MODE_STA");
esp_netif_t *esp_netif_sta = wifi_init_sta();
/* Start WiFi */
ESP_ERROR_CHECK(esp_wifi_start() );
/*
* Wait until either the connection is established (WIFI_CONNECTED_BIT) or
* connection failed for the maximum number of re-tries (WIFI_FAIL_BIT).
* The bits are set by event_handler() (see above)
*/
EventBits_t bits = xEventGroupWaitBits(s_wifi_event_group,
WIFI_CONNECTED_BIT | WIFI_FAIL_BIT,
pdFALSE,
pdFALSE,
portMAX_DELAY);
/* xEventGroupWaitBits() returns the bits before the call returned,
* hence we can test which event actually happened. */
if (bits & WIFI_CONNECTED_BIT) {
ESP_LOGI(TAG_STA, "connected to ap SSID:%s password:%s",
EXAMPLE_ESP_WIFI_STA_SSID, EXAMPLE_ESP_WIFI_STA_PASSWD);
} else if (bits & WIFI_FAIL_BIT) {
ESP_LOGI(TAG_STA, "Failed to connect to SSID:%s, password:%s",
EXAMPLE_ESP_WIFI_STA_SSID, EXAMPLE_ESP_WIFI_STA_PASSWD);
} else {
ESP_LOGE(TAG_STA, "UNEXPECTED EVENT");
return;
}
/* Set sta as the default interface */
esp_netif_set_default_netif(esp_netif_sta);
/* Enable napt on the AP netif */
if (esp_netif_napt_enable(esp_netif_ap) != ESP_OK) {
ESP_LOGE(TAG_STA, "NAPT not enabled on the netif: %p", esp_netif_ap);
}
}Download Full Code
Conclusion
Congratulations, you’ve embarked on a journey to become an ESP32 WiFi connectivity pro! In this guide, we’ve covered both Station(STA mode) and Access Point (AP modes), explaining how to configure WiFi settings using “menuconfig” and providing complete code examples for each mode.
As you continue your ESP32 adventures, remember that practice and experimentation are key. WiFi connectivity opens the door to countless IoT projects, from home automation to remote monitoring. So, keep coding, keep experimenting, and let your creativity soar with the limitless possibilities of ESP32!
Feel free to explore more advanced topics, like handling multiple WiFi interfaces, implementing secure connections, or integrating your ESP32 with cloud services. Your journey has just begun, and there’s a world of IoT innovation waiting to be unlocked.
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