【打卡帖】7日玩转ESP32——(第3日) 通过按键控制扫描并输出附近WiFi AP信息

2023-10-10 14:44:40

文章目录

一、知识点
二、参考例程
三、今日作业
四、参考答案
五、打卡~

一、知识点

ESP32的官方已经将WiFi相关的使用封装成 Wi-Fi 库，并提供API供用户使用。更加方便好上手。

1.1 扫描所有有效的AP

config，扫描的配置
block，是否堵塞程序运行

/**
  * @brief     Scan all available APs.
  *
  * @attention If this API is called, the found APs are stored in WiFi driver dynamic allocated memory and the
  *            will be freed in esp_wifi_scan_get_ap_records, so generally, call esp_wifi_scan_get_ap_records to cause
  *            the memory to be freed once the scan is done
  * @attention The values of maximum active scan time and passive scan time per channel are limited to 1500 milliseconds.
  *            Values above 1500ms may cause station to disconnect from AP and are not recommended.
  *
  * @param     config  configuration of scanning
  * @param     block if block is true, this API will block the caller until the scan is done, otherwise
  *                         it will return immediately
  *
  * @return
  *    - ESP_OK: succeed
  *    - ESP_ERR_WIFI_NOT_INIT: WiFi is not initialized by esp_wifi_init
  *    - ESP_ERR_WIFI_NOT_STARTED: WiFi was not started by esp_wifi_start
  *    - ESP_ERR_WIFI_TIMEOUT: blocking scan is timeout
  *    - ESP_ERR_WIFI_STATE: wifi still connecting when invoke esp_wifi_scan_start
  *    - others: refer to error code in esp_err.h
  */
esp_err_t esp_wifi_scan_start(const wifi_scan_config_t *config, bool block);

1.2 获取上次扫描中找到的AP列表

number，返回的最大ap个数
ap_records，返回的app记录数组

/**
  * @brief     Get AP list found in last scan
  *
  * @param[inout]  number As input param, it stores max AP number ap_records can hold.
  *                As output param, it receives the actual AP number this API returns.
  * @param         ap_records  wifi_ap_record_t array to hold the found APs
  *
  * @return
  *    - ESP_OK: succeed
  *    - ESP_ERR_WIFI_NOT_INIT: WiFi is not initialized by esp_wifi_init
  *    - ESP_ERR_WIFI_NOT_STARTED: WiFi is not started by esp_wifi_start
  *    - ESP_ERR_INVALID_ARG: invalid argument
  *    - ESP_ERR_NO_MEM: out of memory
  */
esp_err_t esp_wifi_scan_get_ap_records(uint16_t *number, wifi_ap_record_t *ap_records);

1.3 获取上次扫描中找到的AP数

number，存储上次扫描中找到的API数

/**
  * @brief     Get number of APs found in last scan
  *
  * @param[out] number  store number of APs found in last scan
  *
  * @attention This API can only be called when the scan is completed, otherwise it may get wrong value.
  *
  * @return
  *    - ESP_OK: succeed
  *    - ESP_ERR_WIFI_NOT_INIT: WiFi is not initialized by esp_wifi_init
  *    - ESP_ERR_WIFI_NOT_STARTED: WiFi is not started by esp_wifi_start
  *    - ESP_ERR_INVALID_ARG: invalid argument
  */
esp_err_t esp_wifi_scan_get_ap_num(uint16_t *number);

二、参考例程

ESP-IDF 中有一个WiFi Fast Scan的例程，实现的是扫描附近WiFi AP。可以参考。

三、今日作业

基于ESP32-C3-DevKitM开发板
开机扫描附近WiFi AP信息
按键短按，按顺序输出打印扫描到的WiFi AP信息
按键长按，重新扫描附近WiFi AP信息，并全部输出打印

四、参考答案

独立完成，明天来看~

五、打卡~

作业完成后，别忘了跟帖打卡（附上源码和图片）~

完成打卡的每人可有新程序员杂志。并且根据完成质量和打卡时间，评选出一二三和特等奖，并送出精美礼品~

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