IoT Forest Fire Early Warning Node with Smoke Sensing

Forest fires spread fastest in their first minutes, yet most forest patches have no continuous sensing — discovery still depends on patrols, towers or bystanders. An always-on, solar-powered node that reports smoke and heat anomalies over kilometres of forest with no cellular or Wi-Fi coverage is the practical answer, and LoRa fits that link exactly. This project builds a remote LoRa sensor node carrying an MQ-2 smoke sensor and a DHT22 temperature-humidity sensor, powered by a small solar panel with battery backup. Nodes report on a configurable interval to a LoRa gateway, which forwards readings to a dashboard that maps each node, shows live gauges and history charts, and raises early-warning alerts when smoke or temperature crosses user-configured thresholds. The deliverable is demonstrated as a multi-node demo network with the full sensor-to-alert chain working: real uplinks, a real alert banner, and a timestamped event log. It is an educational prototype — it demonstrates long-range IoT sensing and threshold-based alerting, and it is explicitly not a certified fire-safety or fire-detection system.

1. The ESP32 wakes on a timer, powers the MQ-2 and DHT22, and samples smoke (analog voltage) plus temperature and humidity.
2. Readings are packed into a compact LoRa payload with the node ID and battery voltage, then transmitted on 433 MHz at the configured spreading factor.
3. The gateway's LoRa receiver decodes the packet and forwards it over Wi-Fi to the dashboard backend.
4. The dashboard updates the node's map marker, gauges and history chart, and logs the reading with a timestamp.
5. If smoke or temperature exceeds the configured threshold for the configured number of consecutive readings, the alert state is raised.
6. On alert, the dashboard shows the warning banner, the gateway buzzer sounds, and notifications are queued to the configured recipients.
7. Between readings the node returns to deep sleep, stretching the solar-charged battery across cloudy days.

Tech stack:

• ESP32 (node controller + gateway controller)
• SX1278 LoRa modules, 433 MHz ISM
• MQ-2 smoke/gas sensor, DHT22 temperature-humidity sensor
• 5 V solar panel, 18650 Li-ion battery, TP4056 charger
• Arduino (C++) firmware
• Gateway dashboard: HTML, CSS, JavaScript

• [Smoke plus climate sensing] An MQ-2 smoke/gas sensor and a DHT22 temperature-humidity sensor are sampled together on every reading, so abnormal heat confirms a smoke event instead of one signal triggering alone.
• [LoRa long-range uplink] An SX1278 LoRa radio (433 MHz ISM) carries readings to the gateway from kilometres away — no Wi-Fi or cellular coverage needed in the forest patch.
• [Solar-powered node] A 5 V solar panel charges a Li-ion battery through a TP4056 module, and the ESP32 sleeps between readings, targeting multi-day autonomy without sun (design target).
• [Gateway dashboard] The dashboard maps every node, shows per-node gauges for smoke/temperature/humidity/battery, 24-hour history charts, configurable thresholds and a timestamped alert event log.
• [Threshold early-warning alerts] User-set smoke and temperature limits; a configurable number of consecutive breaches raises an alert banner, sounds the gateway buzzer and queues notifications.
• [Configurable without reflashing] Node ID, uplink interval and alert thresholds are set in firmware configuration, so tuning for the demo needs no code rebuild.
• [Field calibration procedure] A documented baseline procedure records ambient smoke levels and sets thresholds above the noise floor — no detection accuracy is invented or claimed.
• [Viva-ready documentation] Report with LoRa link budget, sensor datasheets, threshold design rationale and the limitations stated plainly, plus PPT and Q&A.

• Sensor node prototype (ESP32 + SX1278 LoRa + MQ-2 + DHT22, solar-powered)
• LoRa gateway receiver prototype with buzzer output
• Node and gateway firmware (Arduino/C++) with documented configuration
• Gateway dashboard web app (node map, gauges, history, thresholds, event log)
• Wiring diagram and enclosure guidance
• Field calibration and threshold-setting procedure document
• Project report PDF (LoRa link design, sensor datasheets, alert logic, honest limitations)
• PPT presentation for final review
• Viva Q&A preparation document (LoRa modulation basics, MQ-2 sensing principle, power budgeting)

• This is an educational prototype, not certified fire-safety equipment — it must not be presented or used as a real fire-detection or life-safety system.
• The MQ-2 senses smoke crudely; it is not calibrated to any fire standard, and dust, vehicle exhaust or nearby cooking smoke can trigger false alerts.
• No detection accuracy or detection-range figure is claimed — alert thresholds are set by the buyer-run baseline procedure in the calibration document.
• LoRa range of 2–5 km is a design target; hills, dense canopy and antenna placement reduce it, and coverage is not guaranteed.
• Battery autonomy of 3–5 days without sun is a design target, not a measured figure; it depends on panel size, sunlight and uplink interval.
• The gateway needs Wi-Fi to serve the dashboard and send notifications; a node cannot raise an alert if its LoRa link to the gateway is down.
• The dashboard demo ships with simulated data for the viva demonstration; live readings appear when the hardware is connected.