WiFi.scanNetworks() dont work #1355

gerrylenz · 2016-01-02T22:39:22Z

Source
git clone https://github.com/esp8266/Arduino.git esp8266

function
WiFi.scanNetworks();

don't find any networks

reaper7 · 2016-01-07T10:13:37Z

similar problem...
seems that something is wrong, the same example ESP8266WiFi->WiFiScan
sdk 1.3 found 5 AP:

scan start
scan done
5 networks found
1: TP_LINK_ABC (-70) 
2: HP-Print-1e-LaserJet (-83) 
3: NETIASPOT-FF (-89)*
4: NETIASPOT2-FF (-88) 
5: FON_NETIA_ZZZ (-89)

the same example on latest github version (sdk 1.5):

scan start
scan done
4 networks found
1: HP-Print-1e-LaserJet (-83) 
2: NETIASPOT-FF (-89)*
3: NETIASPOT2-FF (-88) 
4: FON_NETIA_ZZZ (-89)

it's looking like the latest sdk version (or wifi lib) do not show first network or skips it

igrr · 2016-01-07T11:17:32Z

Oh, right, I think this was mentioned somewhere. Previously there was a bug
in the SDK, the first node of linked list was always empty. Looks like they
fixed it. Need to update our code as well.

On Thu, Jan 7, 2016, 18:13 reaper7 [email protected] wrote:

similar problem...
seems that something is wrong, the same example ESP8266WiFi->WiFiScan
sdk 1.3 found 5 AP:

scan start
scan done
5 networks found
1: TP_LINK_ABC (-70)
2: HP-Print-1e-LaserJet 100 (-83)
3: NETIASPOT-FF (-89)*
4: NETIASPOT2-FF (-88)
5: FON_NETIA_ZZZ (-89)

the same example on latest github version (sdk 1.5):

scan start
scan done
4 networks found
1: HP-Print-1e-LaserJet 100 (-83)
2: NETIASPOT-FF (-89)*
3: NETIASPOT2-FF (-88)
4: FON_NETIA_ZZZ (-89)

it's looking like the latest version sdk or wifi lib do not show first
network or skips it

—
Reply to this email directly or view it on GitHub
#1355 (comment).

marvinroger · 2016-01-09T19:04:45Z

Yes, I can also confirm this behavior on 2.1.0-rc1.

tzapu · 2016-01-21T13:09:13Z

this still seems to be the issue with the latest github as well, is that correct?

tzapu · 2016-01-22T07:13:19Z

is the fix for this just in the example?
i am not adding +1 to the index and some networks, if not all are missing from int n = WiFi.scanNetworks(); ...
and from what users are reporting, if they revert to esp8266 2.0.0 all is good...

Links2004 · 2016-01-22T12:46:36Z

@tzapu I had misunderstand the problem.
but i not finde the skipping of the first result in the source that @igrr noted.

tzapu · 2016-01-22T14:22:08Z

@Links2004 no problem.

It seems WiFi.scanNetworks(); is not working properly, not finding some or all of networks in latests sdks

I am not sure how to go about replicating it... for instance, i have my own access point that does not appear in the scan, but if i enter ssid and pass manually, it works just fine

cheers

reaper7 · 2016-01-29T13:22:13Z

WiFi.scanNetworks() still do not working properly :(

WifiScan example show 5 networks - do not show(or find?) TP-LINK_XXXXXX network.

But this network are in range because ESP can connect to it (without any problems!) with other examples like WiFiWebServer etc!
As You see, windows machine find TP-LINK_XXXXXX network too, and this is network with strongest signal strength.

look at screenshot:

Links2004 · 2016-01-29T13:25:07Z

@igrr can you fix it?
i not find the offset you noted here:
#1355 (comment)
in our git.

reaper7 · 2016-01-29T13:27:13Z

it looks like first found network are "under index 0"

igrr · 2016-01-29T16:36:23Z

Looks like the code has changed — I was referring to an older version which I wrote initially.
Will take a look.

reaper7 · 2016-02-04T06:02:51Z

now works ok :)
TNX!

tzapu · 2016-02-04T07:24:52Z

i can also confirm it s working, thank you very much

pieman64 · 2016-02-10T15:26:44Z

Thanks for the scan fix which I think I have completed. It seems better now but I'm not 100% convinced I have it right. One router is 6" from my PC and reads 100%, the main router next door is 76% but when I keep scanning over and over again I see one or the other plus lots of 20% to 50% routers but never both of mine together. That suggests I might still be missing the first index in the scan or ESP's are a little crazy. The closest router is a bridge from the main router so I guess that could be the reason it only sees one but they do have different SSID's. Also with the 100% router switched off it takes 5 to 10 rescans to find the 76% router even though each scan is finding 6 or 7 20% to 50% routers. Is this normal behaviour from the ESP's or am I still missing the first index?

pieman64 · 2016-02-10T15:39:59Z

After around 70 or 80 scans I finally see both my routers. Strange little things these ESP's.

Links2004 · 2016-02-10T16:23:23Z

your scan look like there are many routers out there,
do you ever see more then 12 at once?
may there is a limit in the SDK how many they scan.

tzapu · 2016-02-10T16:39:09Z

i am not 100% positive, but i think i have seen more than 12 ....
i hope i am not wrong, not in an area where i can test right now

tzapu · 2016-02-10T16:41:47Z

i was wrong, i can test
i am seeing 14 APs currently

pieman64 · 2016-02-10T17:12:49Z

12 is about the most I have seen but each scans seems to bring up different AP's. Or perhaps I should say not exactly the same 6 to 12 it found on the previous scan. Sometimes very different and sometimes missing both of my 100% and 75% AP's.

pieman64 · 2016-02-10T18:18:36Z

Just seen 13 AP's, none of which were my AP's.

tablatronix · 2016-02-19T16:35:07Z

Could it be channel collisions or a specific mode, I remember seeing someone having an issue with B routers. Channel collisions ?

Mine fluctuates from 22- 27 aps

/*
 *  This sketch demonstrates how to scan WiFi networks. 
 *  The API is almost the same as with the WiFi Shield library, 
 *  the most obvious difference being the different file you need to include:
 */
#include "ESP8266WiFi.h"

void setup() {
  Serial.begin(115200);
  // Serial.setDebugOutput(true);

  // Set WiFi to station mode and disconnect from an AP if it was previously connected
  WiFi.mode(WIFI_STA);
  WiFi.disconnect();

  delay(100);

  Serial.println("Setup done");
  Serial.println();
  Serial.println("MAC: " + WiFi.macAddress());
}

String encryptionTypeStr(uint8_t authmode) {
    switch(authmode) {
        case ENC_TYPE_NONE:
            return "NONE";
        case ENC_TYPE_WEP:
            return "WEP";
        case ENC_TYPE_TKIP:
            return "TKIP";
        case ENC_TYPE_CCMP:
            return "CCMP";
        case ENC_TYPE_AUTO:
            return "AUTO";
        default:
            return "?";
    }
}

void loop() {
  Serial.println("scan start");

  // WiFi.scanNetworks will return the number of networks found
  int n = WiFi.scanNetworks(false,true);
  Serial.println("scan done");
  if (n == 0)
    Serial.println("no networks found");
  else
  {

    // sort by RSSI
    int indices[n];
    for (int i = 0; i < n; i++) {
      indices[i] = i;
    }
    for (int i = 0; i < n; i++) {
      for (int j = i + 1; j < n; j++) {
        if (WiFi.RSSI(indices[j]) > WiFi.RSSI(indices[i])) {
          //int temp = indices[j];
          //indices[j] = indices[i];
          //indices[i] = temp;
          std::swap(indices[i], indices[j]);
        }
      }
    }

    Serial.print(n);
    Serial.println(" networks found");

    Serial.println("00: (RSSI)[BSSID][hidden] SSID [channel] [encryption]");
    for (int i = 0; i < n; ++i)
    {
      // Print SSID and RSSI for each network found
      // Serial.print(i + 1);
      Serial.printf("%02d", i + 1);
      Serial.print(":");

      Serial.print(" (");
      Serial.print(WiFi.RSSI(indices[i]));
      Serial.print(")");

      Serial.print(" [");
      Serial.print(WiFi.BSSIDstr(indices[i]));
      Serial.print("]");

      Serial.print(" [");
      Serial.print((String) WiFi.isHidden(indices[i]));
      Serial.print("]");

      Serial.print(" " + WiFi.SSID(indices[i]));
      // Serial.print((WiFi.encryptionType(indices[i]) == ENC_TYPE_NONE)?" ":"*");

      Serial.print(" [");
      Serial.printf("%02d",(int)WiFi.channel(indices[i]));
      Serial.print("]");

      Serial.print(" [");
      Serial.print((String) encryptionTypeStr(WiFi.encryptionType(indices[i])));
      Serial.print("]");

      Serial.println();
      delay(10);
    }
  }
  Serial.println("");

  // Wait a bit before scanning again
  delay(10000);
}

tablatronix · 2016-02-20T21:20:15Z

I am also now seeing something similar after testing for a bit, for example my home router disappearing from scans now and then, maybe 2 out of 10 times

EDIT
I thought i pulled in 1d14956, but I had not. Working better now

EDIT
Spoke to soon still occurs, it is very odd.

tablatronix · 2016-02-21T19:16:37Z

Threw nodemcu on my chip and am not seeing this behavior. Ill keep looking into it.

tablatronix · 2016-02-27T17:26:08Z

Well more testing and cannot reproduce now. Might be some channel interference, or fast scan switching modes, but my home ap is showing up in every scan now on 2 boards after thousands of scans. Will post details if it occurs again or I can isolate the operating mode

igrr · 2016-02-29T09:23:55Z

This one is getting quite long, and the original bug has been fixed. @tablatronix please open a new issue if you are able to reproduce it.

AnanthaChakravarthi · 2018-04-09T11:42:33Z

hi everyone
i am facing an issue with my esp8266.
it is showing 16 networks at a time and 9 at the other instant. when i check it with mobile there are more than 23 networks. can u suggest me what to do to get all the network ids.

aspiringguru · 2018-07-03T01:40:31Z

AnanthaChakravarthi : I'm guessing different antenna & wifi chips will have different success rates at detecting wifi networks. likely the esp8266 has poorer quality antenna and wifi chip than your mobile has.

I'm still curious if this is a hardware thing, or software delays needed to allow 'better' finding of wifi ssid's.

search2074 · 2018-10-17T18:07:51Z

Worked for me:

It's only helped

``` /* This sketch demonstrates how to scan WiFi networks. The API is almost the same as with the WiFi Shield library, the most obvious difference being the different file you need to include: */ #include "ESP8266WiFi.h"

void setup() {
Serial.begin(115200);

// Set WiFi to station mode and disconnect from an AP if it was previously connected
WiFi.mode(WIFI_STA);
WiFi.disconnect();
delay(100);

Serial.println("Setup done");
}

void loop() {
WiFi.mode(WIFI_STA);
WiFi.disconnect();
delay(100);

Serial.println("scan start");

// WiFi.scanNetworks will return the number of networks found
int n = WiFi.scanNetworks();
Serial.println("scan done, wifi routers: ");
Serial.print(n);

if (n == 0) {
Serial.println("no networks found");
} else {
Serial.print(n);
Serial.println(" networks found");
for (int i = 0; i < n; ++i) {
// Print SSID and RSSI for each network found
Serial.print(i);
Serial.print(": ");
Serial.print(WiFi.SSID(i));
Serial.print(" (");
Serial.print(WiFi.RSSI(i));
Serial.print(")");
Serial.println((WiFi.encryptionType(i) == ENC_TYPE_NONE) ? " " : "*");
delay(10);
}
}
Serial.println("");

// Wait a bit before scanning again
delay(5000);
}

</details>

This was referenced Jan 21, 2016

Errors tzapu/WiFiManager#72

Closed

module with WiFiManager does not see other esp8266 modules in scanNetworks tzapu/WiFiManager#38

Closed

igrr added a commit that referenced this issue Feb 3, 2016

Fix WiFi scan issue (#1355)

1d14956

Links2004 mentioned this issue Feb 4, 2016

Non-persistent behavior with WebSocketServer_LEDcontrol #1568

Closed

krzychb mentioned this issue Feb 10, 2016

Doesn't see any AP with Arduino IDE [Ai-Cloud inside ESP8266 - Black] #1614

Closed

igrr closed this as completed Feb 29, 2016

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

WiFi.scanNetworks() dont work #1355

WiFi.scanNetworks() dont work #1355

gerrylenz commented Jan 2, 2016

reaper7 commented Jan 7, 2016

igrr commented Jan 7, 2016

marvinroger commented Jan 9, 2016

tzapu commented Jan 21, 2016

tzapu commented Jan 22, 2016

Links2004 commented Jan 22, 2016

tzapu commented Jan 22, 2016

reaper7 commented Jan 29, 2016

Links2004 commented Jan 29, 2016

reaper7 commented Jan 29, 2016

igrr commented Jan 29, 2016

reaper7 commented Feb 4, 2016

tzapu commented Feb 4, 2016

pieman64 commented Feb 10, 2016

pieman64 commented Feb 10, 2016

Links2004 commented Feb 10, 2016

tzapu commented Feb 10, 2016

tzapu commented Feb 10, 2016

pieman64 commented Feb 10, 2016

pieman64 commented Feb 10, 2016

tablatronix commented Feb 19, 2016

tablatronix commented Feb 20, 2016

tablatronix commented Feb 21, 2016

tablatronix commented Feb 27, 2016

igrr commented Feb 29, 2016

AnanthaChakravarthi commented Apr 9, 2018

aspiringguru commented Jul 3, 2018

search2074 commented Oct 17, 2018

WiFi.scanNetworks() dont work #1355

WiFi.scanNetworks() dont work #1355

Comments

gerrylenz commented Jan 2, 2016

reaper7 commented Jan 7, 2016

igrr commented Jan 7, 2016

marvinroger commented Jan 9, 2016

tzapu commented Jan 21, 2016

tzapu commented Jan 22, 2016

Links2004 commented Jan 22, 2016

tzapu commented Jan 22, 2016

reaper7 commented Jan 29, 2016

Links2004 commented Jan 29, 2016

reaper7 commented Jan 29, 2016

igrr commented Jan 29, 2016

reaper7 commented Feb 4, 2016

tzapu commented Feb 4, 2016

pieman64 commented Feb 10, 2016

pieman64 commented Feb 10, 2016

Links2004 commented Feb 10, 2016

tzapu commented Feb 10, 2016

tzapu commented Feb 10, 2016

pieman64 commented Feb 10, 2016

pieman64 commented Feb 10, 2016

tablatronix commented Feb 19, 2016

tablatronix commented Feb 20, 2016

tablatronix commented Feb 21, 2016

tablatronix commented Feb 27, 2016

igrr commented Feb 29, 2016

AnanthaChakravarthi commented Apr 9, 2018

aspiringguru commented Jul 3, 2018

search2074 commented Oct 17, 2018