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)
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)
See YT playlist for existing tutorials in the links (I documented most facets of the build in standalone related videos which when all combines- make this project) Handy eh?
Here's a fun little summary of the things I think this project has directly taught me or drastically improved by doing it. Maybe it might be of interest to you to learn them too if you make this project!
- PCB/Design in Fritzing- I could do a bit but now its much easier (no longer needed see below)
- OpenSCAD- Had never used it before this project. Now it makes total sense and makes customizable files found on Thingiverse WAAAAY easier than their customizer
- Fusion 360- I had ZERO experience and now I have fully customized enclosures I can use for this and ANY other project. I actually look forward to my next 3D designs now
- KiCAD- I had never used this and now I have created a functional schematic and PCB from start to finish.
- RF design/Testing- I bought NanoVNAs and learned to use them in order to optimize the antennas for this project. I'm no RF expert but this project has made me learn a TONNE
- HackRF/SDR- I was pretty good with SDR basics but this project let me use the HACKRF and portapack to do testing/validation in the field easily while learning a tonne!
- Spectrum Analyzer- Bought a used lab grade unit so I can keep learing more about this wonderful RF world while I further develop this project
Check out the project logs to how these unfolded :) I hope you enjoy this project as much as I have...Read more »