WIFI channel sensor for ESP-IDF framework

ESPHome
10

C files listed under “esphome: / includes:” get compiled and linked automatically. They can #include esp-idf framework header files. Also, header files listed under “esphome: / includes:” get included by the generated main.cpp and can declare functions so that they can be called from lambdas. For example, this can be placed in the esphome: section:

  includes:
    - idfWifi.h
    - idfWifi.c

and when idfWifi.h contains this:

extern "C"
    {
    int idfWifiGetChannelNum (void);
    }

and idfWifi.c contains this:

#include "esp_wifi.h"

int idfWifiGetChannelNum (void)
    {
    wifi_ap_record_t ap_info;

    if (esp_wifi_sta_get_ap_info (&ap_info) != ESP_OK)
        return (-1);

    return (ap_info.primary);
    }

then esphome yaml code can define a text_sensor using code like this:

text_sensor:
  - platform: template
    id: wifi_channel
    name: "Net WiFi Channel"
    lambda: |-
      static char str[3]; // two digits (or -1) plus NULL
      sprintf(str, "%2d", idfWifiGetChannelNum());
      return (std::string) str;

I tested this with idf 5.2.1 and platformio 6.7.0 and it worked. YMMV, Maarten

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