makio2

WiFi-based multi-sensor RSSI triangulation and occupancy tracking system. Three ESP microcontrollers passively capture 802.11 frames from nearby devices, correlate signal strengths across sensors, and feed data to Supabase for real-time analysis and positioning.

Hardware

Component	Role	Qty
ESP8266 (ESP12F)	Central hub — receives reports from ESP32s and relays everything to the host over serial	1
ESP32	Dedicated channel-hopping sniffers (DEVICE_ID 1 and 2)	2

Architecture:

1. ESP32 #1 and #2 hop channels 1–13, capturing RSSI per MAC
2. Every 30 seconds each ESP32 injects a report frame (magic bytes DE AD BE EF) to the hub on channel 6
3. The ESP12F hub forwards all data — its own captures plus both ESP32 reports — over serial to a host machine
4. Host Python scripts correlate signals or upload to Supabase

Quick Start

1. Flash firmware

# Flash the ESP12F hub
./flash_hub.sh /dev/ttyUSB1

# Flash ESP32 #1 and #2 (pass DEVICE_ID and port)
./flash_esp32.sh 1 /dev/ttyUSB0
./flash_esp32.sh 2 /dev/ttyUSB2

Flashing uses PlatformIO under the hood.

2. Install Python dependencies

pip install -r requirements.txt

3. Run

Live serial monitor (raw output from both boards):

./monitor.sh /dev/ttyUSB0 /dev/ttyUSB1

Local RSSI correlator (rolling average table across all three sensors):

python correlator.py /dev/ttyUSB1 --interval 10 --window 10

Supabase bridge (uploads packet reports in real-time):

python supabase_bridge.py /dev/ttyUSB1 --interval 0.5

Configuration

Supabase credentials (.env)

VITE_SUPABASE_URL=<your-supabase-url>
VITE_SUPABASE_ANON_KEY=<your-anon-key>
VITE_MAPTILER_API_KEY=<optional-maptiler-key>

See supabase_instructions.md for the required table schema and epoch correction details.

Firmware flags (platformio.ini)

Flag	Default	Description
DEVICE_ID	2	Sniffer identity (1 or 2)
HUB_CHANNEL	6	Channel the hub listens on for ESP32 reports
HOP_INTERVAL_MS	50	Dwell time per channel (ms)
REPORT_INTERVAL_MS	30000	How often ESP32s send reports (ms)
REPORT_RETRIES	8	Retransmit count per report burst
MAX_ENTRIES	100 / 200	Max unique MACs tracked (ESP32 / hub)

Script arguments

correlator.py

PORT                 Serial port (default: /dev/ttyUSB1)
--baud BAUD          Baud rate (default: 115200)
--interval SECS      Print interval in seconds (default: 10)
--window N           Rolling average window size (default: 10)

supabase_bridge.py

PORT                 Serial port (default: /dev/ttyUSB1)
--baud BAUD          Baud rate (default: 115200)
--interval SECS      Min seconds between uploads per MAC (default: 0.5)

How It Works

Channel hopping

Both ESP32s use a weighted hop sequence that visits the three non-overlapping channels (1, 6, 11) more frequently:

1, 2, 6, 3, 4, 11, 5, 6, 7, 11, 8, 9, 6, 10, 11, 12, 13, 1

One full cycle is 18 steps × 50 ms = 900 ms.

Timestamp correction

Boards record millis() (uptime), not wall-clock time. The Python host anchors each entry to real Unix time:

sniff_unix = python_rx_time - (report_ms - timestamp_ms) / 1000.0

Where report_ms is the board's clock at transmission and timestamp_ms is when each MAC was sniffed.

Data format

Each sniffed entry is a 12-byte packed struct:

struct __attribute__((packed)) PktEntry {
    uint8_t  mac[6];         // device MAC address
    int8_t   rssi;           // signal strength (dBm)
    uint8_t  channel;        // channel sniffed on
    uint32_t timestamp_ms;   // board uptime at capture
};

Dependencies

• Python: pyserial, supabase, python-dotenv
• Firmware: Arduino framework, ESP-IDF WiFi (ESP32), NonOS SDK (ESP8266), via PlatformIO