SD-F
Handheld surveillance detection and direction finding.
A handheld device that detects nearby surveillance hardware, such as Flock Safety cameras, Ring doorbells and drones, and points you toward where it is.
Overview
Knowing that a surveillance device is nearby is a good start. Knowing where it is matters more. The SD-F (Surveillance Detection & Finding) scans 2.4 GHz Wi-Fi and Bluetooth LE, flags known surveillance hardware, and estimates the bearing to a selected target on a built-in screen.
It finds direction with a directional antenna and a motion sensor. Sweep the device slowly through a turn: the firmware tracks signal strength against compass heading and reports the direction where the signal peaks. An omni reference antenna cancels out changes in range and transmit power during the sweep.
The antennas are poured-copper designs on their own daughter board, simulated to resonate in the 2.4 GHz band. The first boards came back with defects, and the next revision fixes them along with several usability improvements.
Build log Wrewtopia Labs WX-2E SD-F
Specs
Design targets for the current revision. Final hardware may change.
| MCU | ESP32-S3 module (Wi-Fi + Bluetooth LE) |
|---|---|
| Detects | 2.4 GHz Wi-Fi and Bluetooth LE emitters |
| Antennas | Built-in copper patch (directional) + omni reference, external SMA option |
| Heading | BNO085 9-axis IMU with on-chip sensor fusion |
| Display | 2.0" 240×320 IPS |
| Controls | Rotary encoder with push + tactile buttons |
| Power | Single-cell Li-ion, USB-C charging |