Architecture Overview
Continuous non-invasive telemetry provides early warning indicators for colony health, nectar flow velocity, queen failure, and impending swarm departures without disrupting the delicate brood microclimate. The BuenoBee Precision Hive System employs ultra-low-power LoRaWAN nodes deployed across Mayagüez apiaries transmitting telemetry over a 12 km non-line-of-sight mountainous corridor.
1. Hardware Schematic & Sensor Topology
[2.5W Solar Mini-Panel] ──► [TP4056 + 18650 Li-ion 3400mAh]
│
▼
[ESP32-S3 Microcontroller (Deep Sleep 14uA)]
│
├── I2C Bus:
│ ├── Sensirion SHT40 (Ambient Temp / Humidity)
│ └── HX711 24-Bit ADC (4x 50kg Load Cells in Baseboard)
│
├── 1-Wire Bus:
│ └── 2x Waterproof DS18B20 Probes (Brood Core + Super)
│
├── I2S Audio:
│ └── INMP441 MEMS Microphone (Internal Hive Acoustics)
│
└── SPI Bus:
└── Semtech SX1262 LoRaWAN Transceiver (US915 MHz, +20dBm)2. Edge Fast Fourier Transform (FFT) for Swarm Detection
When a colony enters reproductive swarming mode, worker acoustic vibrations transition from standard 150–220 Hz colony hum into high-amplitude 400–500 Hz piping frequencies. The ESP32 edge node processes a 512-point FFT every 15 minutes:
#include <arduinoFFT.h>
#define SAMPLES 512
#define SAMPLING_FREQUENCY 4000 // 4 kHz sampling captures up to 2 kHz Nyquist
double vReal[SAMPLES];
double vImag[SAMPLES];
ArduinoFFT<double> FFT = ArduinoFFT<double>(vReal, vImag, SAMPLES, SAMPLING_FREQUENCY);
bool detectPreSwarmAcoustics() {
FFT.windowing(FFTWindow::Hamming, FFTDirection::Forward);
FFT.compute(FFTDirection::Forward);
FFT.complexToMagnitude();
double swarmBandEnergy = 0.0;
double baselineEnergy = 0.0;
// Evaluate spectral energy between 400 Hz and 500 Hz
for (int i = 51; i <= 64; i++) { // Bins corresponding to 400-500 Hz
swarmBandEnergy += vReal[i];
}
// Evaluate baseline colony frequency 150-250 Hz
for (int i = 19; i <= 32; i++) {
baselineEnergy += vReal[i];
}
// Ratio anomaly threshold exceeding 1.8 indicates active swarm preparation
return (swarmBandEnergy / baselineEnergy) > 1.80;
}3. LoRaWAN Payload Serialization
To minimize battery drain and comply with regional duty-cycle regulations, all measurements are packed into a compact 12-byte binary payload:
| Byte Offset | Parameter | Data Type | Resolution | Range |
|---|---|---|---|---|
| 0 - 1 | Brood Temperature | int16_t (big-endian) | 0.01 °C | -40.00 to +85.00 °C |
| 2 - 3 | Ambient Temperature | int16_t (big-endian) | 0.01 °C | -40.00 to +85.00 °C |
| 4 | Relative Humidity | uint8_t | 0.5 % RH | 0.0 to 100.0 % |
| 5 - 6 | Gross Hive Mass | uint16_t | 10 grams | 0.00 to 250.00 kg |
| 7 | Acoustic State | uint8_t (bitflags) | Bit 0: Swarm alert | 0 or 1 |
| 8 - 9 | Battery Voltage | uint16_t | 1 millivolt | 2500 to 4200 mV |
| 10 - 11 | Uplink Counter | uint16_t | Integer | 0 to 65535 |
4. Operational Telemetry Checklist
- Verify deep-sleep current draw measures below 18
\mu\text{A}with all sensors powered down via P-channel MOSFET switch. - Calibrate tare weight on dual scale frame with standard 20.0 kg reference test mass.
- Confirm LoRaWAN gateway SNR exceeds +6 dB at the Mayagüez base station.
- Validate automated SMS and email dispatch when brood nest drops below 32.0°C.