Main Content

Ever wonder about all the WiFi around you ? This simple display will graphically show you the surrounding WiFi users. This device continuously scans the local area WiFi channels in promiscuous mode, looks at the headers & tosses the payloads( a bit like reading the envelope but not opening it). We can then grab a list of who is sending & display some information.

Since we don’t want to creep people out too much we only display the lower three bytes of the senders MAC (which is a six byte number) the top bytes are used for manufacture information so the lower 3 tend to be random enough to get a pretty colors(the program further reduces this to 5-6-5 color code) . There are 13channels in N.A. WiFi this is mapped across 16 columns and we make the row signal strength mapped from -30db to -100db. Having the color mapped against the channel & signal would make the display static & we couldn’t know when a signal was moving in or out, decreasing or increasing so we set the display to do a lossy blur so any signal fades to black before being scanned again.

ESP32 -Wrover-B
16x16 led array ws2812b
level shifter
220uf 16V
2.1mm female jack
5v 1-3A supply
Optional: header strip, Dupont female wires , translucent plastic”

Link to article