Telemetry Format

Each smart buoy transmits a telemetry packet at configurable intervals (default: every 15 minutes when idle, immediately on catch events).

Packet Layout

The telemetry payload (opcode 0x81) contains 24 bytes:

Offset	Size	Field	Unit	Description
0	4	`latitude`	1e-7 degrees	Signed 32-bit, WGS84
4	4	`longitude`	1e-7 degrees	Signed 32-bit, WGS84
8	2	`depth_cm`	centimeters	Pressure-derived depth
10	2	`water_temp`	0.1°C	Signed 16-bit
12	2	`battery_mv`	millivolts	Buoy battery voltage
14	1	`solar_state`	enum	0=dark, 1=charging, 2=full
15	1	`door_state`	enum	0=locked, 1=unlocked, 2=fault
16	1	`keeper_count`	count	Classified keepers since last reset
17	1	`bycatch_count`	count	Classified bycatch since last reset
18	1	`release_count`	count	Autonomous releases since last reset
19	1	`classification_mode`	enum	0=auto, 1=manual, 2=log-only
20	2	`uptime_hours`	hours	Time since last reboot
22	1	`rssi`	dBm	Last received signal strength
23	1	`flags`	bitfield	See flag table below

Flags Bitfield

Bit	Name	Description
0	`DRIFT_ALERT`	Position has moved > 50m from deployment point
1	`LOW_BATTERY`	Battery below 3.3V
2	`CAMERA_FAULT`	ESP32-CAM not responding
3	`SERVO_FAULT`	Door servo not responding
4	`GPS_FIX`	1 = valid fix, 0 = no fix
5	`IMAGE_PENDING`	Captured image waiting for download
6–7	Reserved

Telemetry Schedule

Condition	Interval
Idle, no catch	Every 15 minutes
Catch event	Immediate (within 2 seconds)
Alert condition	Immediate + every 5 minutes until resolved
Sleep mode	Disabled (wake-on-command only)

Decoding Example

typedef struct __attribute__((packed)) {
    int32_t  latitude;       // 1e-7 degrees
    int32_t  longitude;      // 1e-7 degrees
    uint16_t depth_cm;
    int16_t  water_temp;     // 0.1°C
    uint16_t battery_mv;
    uint8_t  solar_state;
    uint8_t  door_state;
    uint8_t  keeper_count;
    uint8_t  bycatch_count;
    uint8_t  release_count;
    uint8_t  classification_mode;
    uint16_t uptime_hours;
    int8_t   rssi;
    uint8_t  flags;
} telemetry_t;