esp-idf: ssid のスキャン

esp-idf/examples/wifi/scan/ を参考にしました。
M5Stack Core2 で動作確認をしました。

プログラム

コンパイル前のフォルダー構造

$ tree scan
scan
├── CMakeLists.txt
├── README.md
└── main
    ├── CMakeLists.txt
    └── scan.c

main/CMakeLists.txt

idf_component_register(SRCS "scan.c"
                    INCLUDE_DIRS ".")

main/scan.c

// -----------------------------------------------------------------------
/*
	main/scan.c

					Jan/30/2023
*/
// -----------------------------------------------------------------------
#include <string.h>
#include <unistd.h>

#include "esp_wifi.h"
#include "esp_event.h"
#include "nvs_flash.h"

#define DEFAULT_SCAN_LIST_SIZE 16

#define	VERSION	"2023-1-30 AM 11:29"
// -----------------------------------------------------------------------
static void wifi_scan_aa(void)
{
	ESP_ERROR_CHECK(esp_netif_init());
	ESP_ERROR_CHECK(esp_event_loop_create_default());
	esp_netif_t *sta_netif = esp_netif_create_default_wifi_sta();
	assert(sta_netif);

	wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
	ESP_ERROR_CHECK(esp_wifi_init(&cfg));
}

// -----------------------------------------------------------------------
static void wifi_scan_bb(void)
{
	uint16_t number = DEFAULT_SCAN_LIST_SIZE;
	wifi_ap_record_t ap_info[DEFAULT_SCAN_LIST_SIZE];
	memset(ap_info, 0, sizeof(ap_info));
	uint16_t ap_count = 0;

	ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA));
	ESP_ERROR_CHECK(esp_wifi_start());
	esp_wifi_scan_start(NULL, true);
	ESP_ERROR_CHECK(esp_wifi_scan_get_ap_records(&number, ap_info));
	ESP_ERROR_CHECK(esp_wifi_scan_get_ap_num(&ap_count));

	printf("Total APs scanned = %u\n", ap_count);

	for (int it = 0; (it < DEFAULT_SCAN_LIST_SIZE) && (it < ap_count); it++)
		{
		printf("%d\tSSID \t%s\n", it,ap_info[it].ssid);
		}

	printf("\n");
}

// -----------------------------------------------------------------------
void loop(void)
{
	while (1)
		{
		printf("*** loop *** %s ***\n",VERSION);
		wifi_scan_bb();
		sleep(5);
		}
}

// -----------------------------------------------------------------------
void app_main(void)
{
	// 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 );

	wifi_scan_aa();
	sleep(3);
	printf("*** %s ***\n",VERSION);

	loop();
}

// -----------------------------------------------------------------------

コンパイル、実行

idf.py -p /dev/ttyUSB0 flash

実行結果

*** loop *** 2023-1-30 AM 11:29 ***
Total APs scanned = 11
0	SSID 	Buffalo-G-7008
1	SSID 	rs500m-e1eaf5-2
2	SSID 	rs500m-e1eaf5-1
3	SSID 	TP-Link_E2EE
4	SSID 	C0B47DD1BB49-2G
5	SSID 	DIRECT-D30B7833
6	SSID 	Buffalo-G-37E8
7	SSID 	ssw-pc-639639
8	SSID 	HG8045-549F-bg
9	SSID 	Buffalo-G-8E70-WPA3
10	SSID 	aterm-6c79cc-gw