Proper way of restarting WiFi after WiFi.mode(WIFI_OFF);

[thezenox]

I am running an Upload Task connecting to a WiFiAP (doing a scan and select the best Network) and uploading stuff. If finished uploading, wifi is turned off and the task is deleted.
If I want to upload again, the task ist created again, but I get:
E (345591) wifi: esp_wifi_scan_start 1245 wifi not start

So what is the proper way of turning WiFi off completly (reduce power consumption) and enabeling it again? I already tried different things but can't get it working.

Currently I am doing this:
Start WiFi (only relevant code):

WiFi.mode(WIFI_MODE_STA); // calls esp_wifi_set_mode(WIFI_MODE_STA); and esp_wifi_start();
WiFi.enableSTA(true);
scanResult = WiFi.scanNetworks(); // doing scan
if(scanResult > 0){
 WiFi.begin(ssid, pw); // connecting the best network I have the key for
}

End WiFi:

WiFi.disconnect(true); // calls esp_wifi_disconnect(); and WiFi.enableSTA(false);
WiFi.mode(WIFI_OFF); // calls esp_wifi_stop(); and wifiLowLevelDeinit(); in espWiFiStop();, while wifiLowLevelDeinit is doing nothing, yet https://github.com/espressif/arduino-esp32/blob/2f13a960acd1baf1599d855385c64a2716708f85/libraries/WiFi/src/WiFiGeneric.cpp#L128

Debug results for wifi start (only on first call, nothing if recreating the task):

[D][WiFiGeneric.cpp:332] _eventCallback(): Event: 2 - STA_START
[D][WiFiGeneric.cpp:332] _eventCallback(): Event: 0 - WIFI_READY
[D][WiFiGeneric.cpp:332] _eventCallback(): Event: 1 - SCAN_DONE

Wifi end gives

[D][WiFiGeneric.cpp:332] _eventCallback(): Event: 5 - STA_DISCONNECTED
[W][WiFiGeneric.cpp:348] _eventCallback(): Reason: 8 - ASSOC_LEAVE
[D][WiFiGeneric.cpp:332] _eventCallback(): Event: 3 - STA_STOP

When ending wifi task again because of timeout, I get:
E (505690) wifi: esp_wifi_disconnect 1153 wifi not start

Any Idea what is happening here and how to restart wifi again?

[maribeiro]

There seems to be a bug on the WifiGeneric class
See #3522

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[STALE_SET] This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 14 days if no further activity occurs. Thank you for your contributions.

[stale]

[STALE_DEL] This stale issue has been automatically closed. Thank you for your contributions.

[NOUSHADO]

Dear i am having facing the issue of esp32 Nod mcu going offline i have tried many but , it was suitable your code
i was used in expalexa program exactly working fine
but i am not able to add this code in blynk esp32 program code it was getting error
for this can you suggest me how to use it
any way thanking you very much

#define BLYNK_PRINT Serial

#include <WiFi.h>
#include <WiFiClient.h>
#include <BlynkSimpleEsp32.h>
void setup()
WiFi.mode(WIFI_MODE_STA); // calls esp_wifi_set_mode(WIFI_MODE_STA); and esp_wifi_start();
WiFi.enableSTA(true);
scanResult = WiFi.scanNetworks(); // doing scan
if(scanResult > 0){
WiFi.begin(ssid, pw); // connecting the best network I have the key for
}

// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "";

// Your WiFi credentials.
// Set password to "" for open networks.
char ssid[] = "";
char pass[] = "";

void setup()
{
// Debug console
Serial.begin(9600);

Blynk.begin(auth, ssid, pass);
}

void loop()
{
Blynk.run();
}

[NOUSHADO]

this is the error

Arduino: 1.8.13 (Windows Store 1.8.42.0) (Windows 10), Board: "WeMos WiFi&Bluetooth Battery, 80MHz, 921600, None"

BlynkESP32googleamazone26-03-2021-1:40:1: error: expected initializer before 'WiFi'

WiFi.mode(WIFI_MODE_STA); // calls esp_wifi_set_mode(WIFI_MODE_STA); and esp_wifi_start();

^

BlynkESP32googleamazone26-03-2021-1:41:1: error: 'WiFi' does not name a type

WiFi.enableSTA(true);

^

BlynkESP32googleamazone26-03-2021-1:42:1: error: 'scanResult' does not name a type

scanResult = WiFi.scanNetworks(); // doing scan

^

BlynkESP32googleamazone26-03-2021-1:43:1: error: expected unqualified-id before 'if'

if(scanResult > 0){

^

Multiple libraries were found for "WiFi.h"

Used: C:\Users\noush\OneDrive\Documents\ArduinoData\packages\esp32\hardware\esp32\1.0.5\libraries\WiFi

Not used: C:\Program Files\WindowsApps\ArduinoLLC.ArduinoIDE_1.8.42.0_x86__mdqgnx93n4wtt\libraries\WiFi

exit status 1

expected initializer before 'WiFi'

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

[YordanYanakiev]

static bool wifiLowLevelDeinit(){
    //deinit not working yet!
    //esp_wifi_deinit();
    return true;
}

found this inside the WiFiGeneric.cpp .. (line 148)

so.. the deinit is not going to do anything...