IoT Beehive Monitor using ESP32

Beekeepers still check hive health by opening boxes — disruptive to the colony, infrequent, and easy to postpone until a problem is advanced. Between inspections, a lost queen, an overheating brood nest, a failing nectar flow or a pre-swarm buildup can develop unseen for days. Continuous monitoring helps, but commercial hive scales and sensors are expensive and closed. The engineering answer is a low-cost, non-invasive node: measure the three signals that matter most — brood-box temperature, humidity and total hive weight — and watch their trends instead of opening the hive. The ESP32 fits naturally: Wi-Fi for telemetry, deep sleep for battery life, and enough ADC and digital interfaces for a DHT22 plus an HX711 load-cell amplifier. This project builds the complete system: the sensor node with a weatherproof enclosure, a two-point load-cell calibration the buyer runs on their own stand, threshold and swarm-heuristic logic, and an MQTT dashboard with gauges, climate charts, weight trends and an event log.

1. On each wake cycle the ESP32 reads the DHT22 (temperature, humidity) and the HX711 load-cell amplifier (hive weight, averaged over samples).
2. Readings are compared against configured thresholds: brood over-temperature, humidity extremes, and sudden weight changes.
3. The swarm heuristic evaluates sustained temperature elevation together with weight-pattern changes and raises an inspection flag when both persist.
4. Data is published over Wi-Fi via MQTT with the hive ID, and the node returns to deep sleep until the next cycle.
5. The dashboard renders live gauges, appends to the 24-hour climate chart and the 7-day weight trend, and writes threshold crossings to the event log.
6. Missed uploads are buffered in RTC memory and backfilled when connectivity returns.
7. The buyer calibrates the load cell once with known weights using the included tare/calibration procedure, so weight readings are meaningful on their own stand.

Tech stack:

• ESP32 DevKit (Arduino-core firmware, deep sleep)
• DHT22 temperature-humidity sensor (digital)
• Load cell with HX711 24-bit amplifier
• MQTT broker plus web dashboard (gauges, charts, event log)
• 18650 cell with solar charging module; weatherproof enclosure
• 0.96-inch OLED for on-device readout

• [In-hive temperature & humidity sensing] A DHT22 placed in the brood box reports temperature and humidity on every wake cycle, so overheating or excess moisture shows up on the dashboard instead of at the next inspection.
• [Hive weight tracking] A load cell under the hive stand with an HX711 amplifier tracks total weight; the 7-day trend acts as a proxy for honey stores and daily foraging activity.
• [Swarm-risk heuristic] A sustained brood-temperature rise combined with characteristic weight-pattern changes raises a "inspect this hive" flag — a heuristic aid for the beekeeper, not a guaranteed prediction.
• [MQTT telemetry dashboard] Live gauges for temperature, humidity and weight, 24-hour climate charts, a 7-day weight trend with annotations, and a timestamped event log.
• [Multi-hive support] The dashboard handles up to four hive nodes, each with its own gauges, charts and alert thresholds.
• [Solar deep-sleep operation] The ESP32 sleeps between configurable 5–30 minute wake cycles; a small solar panel tops up the 18650 cell for unattended apiary use.
• [Offline resilience + local display] Readings continue on schedule if Wi-Fi drops and backfill when the link returns; a small OLED shows the last reading at the hive.

• Complete ESP32 firmware (sensing, HX711 averaging, thresholds, swarm heuristic, MQTT, deep sleep, backfill)
• Wiring diagram and weatherproof-enclosure mounting guide
• Load-cell tare and known-weight calibration guide (procedure the buyer runs on their stand)
• MQTT dashboard web app (gauges, charts, weight trend, event log, multi-hive views)
• Project report PDF (background, sensor choice, power budget, evaluation method)
• PPT presentation for final review
• Viva Q&A preparation document (DHT22, HX711, MQTT, deep sleep, calibration, beekeeping basics)
• Setup guide (broker setup, Wi-Fi provisioning, first calibration run)

• Weight is a trend proxy for honey stores and foraging, not a direct measurement of honey mass — rain, wind and beekeeper handling all move the reading, so only multi-day trends are meaningful.
• The DHT22 is a slow, modest-accuracy sensor (datasheet ±0.5 °C); it tracks hive climate trends well but is not a precision instrument.
• The swarm flag is a heuristic inspection aid based on temperature and weight patterns; it does not guarantee swarm prediction and the report states this plainly.
• The node needs a weatherproof enclosure and sensible sensor placement that does not disturb the bees — the mounting guide covers this, but colony behavior varies.
• Wi-Fi range limits apiary placement; the node keeps logging locally and backfills, but the dashboard goes stale until the link returns.
• Electronics are prototype-grade, not apiary-certified equipment; long-term outdoor reliability depends on the enclosure build.