Real-Time Rogue Wireless Access Point Detection with the Raspberry Pi

One thing I always wanted was a passive real-time wireless sensor network to watch for changes in Wi-Fi. A passive system, like Kismet and Airodump-NG, collects all the packets in the radio frequency (RF) that the card can detect and displays them. This finds hidden WAPs too, by looking at the clients talking to them. In contrast, active systems, like the old Netsumbler, try to connect WAPs by broadcasting null SSID probes and displaying the WAPs that reply back.