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Keep WiFi Connection Alive with a FreeRTOS Task

Does your ESP32 need a constant WiFi connection? Use a FreeRTOS task to constantly check your connection, and re-establish it when needed.

This code has been super robust for me. I've been using it for my Home Energy Monitor, and it has been running reliably for years.

I also have a dedicated blog post about this technique.

Full code

#define WIFI_NETWORK "--- your WiFi network name ---"
#define WIFI_PASSWORD "--- your WiFi password ---"
#define WIFI_TIMEOUT_MS 20000 // 20 second WiFi connection timeout

void keepWiFiAlive(void * parameter){
    for(;;){
        if(WiFi.status() == WL_CONNECTED){
            Serial.println("WiFI still connected.");
            vTaskDelay(10000 / portTICK_PERIOD_MS);
            continue;
        }

        Serial.println("WiFi Connecting");
        WiFi.mode(WIFI_STA);
        WiFi.begin(WIFI_NETWORK, WIFI_PASSWORD);

        unsigned long startAttemptTime = millis();

        // Keep looping while we're not connected and haven't reached the timeout
        while (WiFi.status() != WL_CONNECTED && 
                millis() - startAttemptTime < WIFI_TIMEOUT_MS){}

        // When we couldn't make a WiFi connection (or the timeout expired)
        // sleep for a while and then retry.
        if(WiFi.status() != WL_CONNECTED){
            Serial.println("[WIFI] FAILED");
            vTaskDelay(WIFI_TIMEOUT_MS / portTICK_PERIOD_MS);
            continue;
        }

        Serial.println("[WIFI] Connected: " + WiFi.localIP());
    }
}

Useful resources