Join Wi-Fi

Wi-Fi Scan

List nearby APs and RSSI. Used for channel choice and provisioning lists.

Join Wi-Fi Scan networksRSSIprovisioningchannel selection ESP32 Wi-Fi parts

Official path: examples/wifi/scan

01 Overview

Scan prints SSID, RSSI and auth mode. Provisioning UIs are built on this.

Use when: showing networks before join, or hunting interference.

Skip when: already joined and not changing network.

The scan result can be used to pick the best channel or feed a provisioning list.

ESP32 supports active and passive scans, with configurable dwell time and channel.

Note: scanning briefly occupies the radio and may affect an existing connection.

No extra parts: Only the ESP32 module and antenna are needed.
Antenna placement: Metal near the antenna or obstructions change RSSI readings significantly; measure the full unit.
Housing effects: A metal enclosure attenuates signals, so scan results differ from a bare module.
Power: Scanning increases RF power consumption; ensure a stable supply.
Layout: Keep the antenna area clear of traces and components.
Reference design: Follow ESP32 hardware design guidelines for antenna matching and layout.

1. Initialize NVS and Wi-Fi in STA mode.

2. Call esp_wifi_scan_start with desired scan type (active/passive), channel, and max AP count.

3. Wait for scan done event or use blocking API.

4. Get scan results and iterate over AP records, extracting SSID, RSSI, and auth mode.

5. Filter hidden networks (empty SSID) and sort by RSSI descending.

6. Send the list to a provisioning UI via UART or HTTP.

7. Free memory after scan and avoid blocking the main task.

中文

连上 Wi-Fi

列出周围热点和信号，用来选信道、做配网列表。

连上 Wi-Fi 扫描附近网络RSSIprovisioningchannel selection ESP32 Wi-Fi parts

官方路径: examples/wifi/scan

扫描周边 AP，打印 SSID、RSSI、认证类型。配网 App 的列表通常来自这里。

适用： 配网前展示网络、现场干扰排查。

不适用： 已经连上且不需要换网。

扫描结果用于选择最优信道或作为配网列表的数据源。

ESP32 的扫描支持主动和被动模式，可配置扫描时间与信道。

注意：扫描会短暂占用射频，可能影响当前连接。

1. 初始化 NVS 和 Wi-Fi，设置为 STA 模式。

2. 调用 esp_wifi_scan_start，配置扫描类型（主动/被动）、信道和最大 AP 数。

3. 等待扫描完成事件，或使用阻塞 API。

4. 获取扫描结果，遍历 AP 记录，提取 SSID、RSSI、认证模式。

5. 过滤隐藏网络（SSID 为空），按 RSSI 降序排序。

6. 将列表通过 UART 或 HTTP 传给配网 UI。

7. 扫描完成后释放内存，避免阻塞主任务。