This open source project investigates using AP beacon packet sniffing to locate people such as lost hikers, campers and even poachers in game preserves. This works anywhere- as long as wifi is enabled on the targets phone. The hardware detects the beacon frames from their cellular phone, records the GPS coordinates for use later. 2 flavors are made: one hand-held portable and the other airborne carried by plane or drone.

DETAILS

I was inspired by the constant stream of search and rescue operations on the television show “North Woods Law”. Each week they struggled to find lost people in the remote/rugged areas of Maine U.S.A. These areas often have no cellular service but in almost every case the target people had cellphones on them and working. As I live in Canada- we have a surplus of these situations in our vast wilderness as well. I theorized I could use an external 2.4GHz antenna to receive the AP beacon frames from those phones ad capture that data.

This hardware can be embedded in to any very small drone or RC aircraft. It can also be attached to existing manned aircraft already participating in the search.

Using small drone aircraft (like the Nano Talon I use here) gives all the advantages such as flight condition tolerance, height, terrain, time of day etc that drones have over manned aircraft. They can also be sent on the full way-point mission without human intervention and tracked live from any ground station.

What it does (both air unit and ground unit W yagi):

Detects all Beacons and their mac addresses within range
Detects All AP’s in range (not needed but why not log them anyhow)
Gets GPS Lat/Long positioning
Gets GPS UTC Time
Logs all the above to the SD card .csv file every time any device detected changes
Displays the number of clients detected, APs detected, time and Lat/Long on the OLED screen live.
Air unit will eventually send telemetry to ground control for live alerts (likely using existing 433MHz telemetry already sending flight data)

BUILD

I started this build in 2018 and have proven out the Nano Talon airrframe to be a very worthy commercial candidate with good payload and HUGE flight times while operating fully autonomously. The Nano Talon breaks down small for easy transport/storage.

So far I am using the Wedmos D1 mini PRO with an external antenna (YAGI or Rubber duck) to receive the beacon frames, log them to SD Card with RSSI values (adds more precise direction finding if you fly a grid pattern) to review the MAC address list as well as plot with Google Earth/maps. I can easily transmit this via LORA or NRF module to the ground instantly as well. This will be logged as a separate version of the hardware.

I will update this and post the videos as we move forward with publishing (this will take me some time to document properly)