ESP8266 Community Forum

- Tue Mar 08, 2016 10:11 am #42687 Wanted to test a few external antenna configurations. Just wanted to see relative RSSI figures between antennas.

Couldn't find anything simple to bang onto a spare ESP8266 for testing, so quickly wrote this up.

https://github.com/MetalPhreak/ESP8266_wifiscan

Tested on SDK 1.5.2

Just flash onto an ESP8266, connect to the serial port on 76800 baud, and it'll spit out scan results as fast as it can grab them (approx once per second).

http://d.av.id.au

- Wed Mar 09, 2016 3:44 am #42737

Code: Select allStarting Wifi Scan:
scandone
              XXXXXX YYYY 2.4GHz (e2:df:11:a4:17:22) ch: 01 rssi: -68 auth: 03 hidden: 0 freq_offset: 10
                   Telstra123456 (c7:ae:1f:69:2a:44) ch: 01 rssi: -90 auth: 03 hidden: 0 freq_offset: 26
                            WIFI (a1:27:bf:d2:85:7e) ch: 06 rssi: -73 auth: 01 hidden: 0 freq_offset: -6
                 AirWifi RTYUQWE (00:2a:ff:27:75:ad) ch: 06 rssi: -55 auth: 03 hidden: 0 freq_offset: 10
             BigPond123456_2GEXT (22:92:cf:ed:f6:b7) ch: 06 rssi: -89 auth: 03 hidden: 0 freq_offset: 8


Example output (SSIDs and MACs changed to random values for security). Someone near me is still using WEP

http://d.av.id.au

- Tue Apr 05, 2016 8:17 pm #44922 Is there any way to make the scan happen quicker? I seem to be stuck scanning at around 1 second intervals and I need that to come way down if possible. like 20ms if possible.

- Sun Aug 07, 2016 6:38 am #52394 Hi,

I'd like a similar thing, fast(er) scanning.
Although one limitation of wifi scanning, is the dwell time per channel needed.
If you're relying on picking up a beacon, then the device really needs to wait for at least 100mSeconds
per channel, as that's the default beacon interval for most WAPs.
If you don't wait that long, then you may miss the advertisement.
So allowing for 100mS dwell time, 13(?) channels, and perhaps a little bit of time to settle between
frequency changes, and the time starts to add up...

If you want FAST display of a specific SSID, then if you can attach to it, then that seems to work fine by
(i think) simply reading WiFi.RSSI(), and displaying it as fast as you can read it.

But using wifiscan is going to be slow (due to the limitations of relying on beacons), unless the channels to be scanned can be limited...