This happened sometime ago, when I started working on a ECU project related to WiFi. One of the good things about my workplace is that we test our ECU/Devices on  an isolated network that allows for us to reach out to internet but not directly reach to Cat’s Internal Servers, when working from inside the Caterpillar Engineering Office.

I was testing my devices against various connectivity modes only to find the very next day the primary test WiFi SSID disappeared from the WiFi Scan for my devices. I dug in trying to run WiFi scans using my wpa_supplicant, only to find that the SSID had disappeared. I tried Network Analyzer on my Android app and confirmed that 5GHz version of the WiFi was not available in my location. Coincidentally, my regression test setup was not having issues and, it has been working fine.

With that, I determined that its a hunt for WiFi and needed a better scanner. A fair note is that the 2.4GHzband is the only ones over which the ECU (Be aware these are legacy devices) operate. I need a compact devices that searches for signal strength and spits out all the WiFi networks nearby. The solution is a device that I can carry around and, one that is dedicated to this function.

Enter ESP32, these tiny little buggers have WiFi and BLE and about 40 GPIO and can literally do a lot of things from driving displays, morors, SD Cards, Audio DACs and etc,.

These devices work with FreeRTOS and Arduino. They are also cross-compatible with a lot of ardunio libraries, adding even more value to them. So there I was starting up my own wifi scanner which scans and logs for WiFi SSIDs nearby. I wrote it to log a couple of information including SSID, RSSI, Channel, BSSID and, Authentication Type.

The initial prototype was monochromatic and looked shabby.

The prototype did the job of SSID but, was really bad at getting the signal strength shown clearly. So it was time to color code the entire thing and, went with version 2!

Once done, The final product looked like the one below. I went around snooping to find the best WiFi Spot to stash away the devices as well as ended up testing the devices with worst WiFi signals.

 

 

You can find the code for the scanner at Github under my name.