Sensor Nodes
Every PlantHub sensor node packs four environmental sensors into a compact, weatherproof ESP32-C3 module. Capacitive soil moisture, air temperature, humidity, and ambient light — all pushing data over encrypted MQTT in real time. Self-provisioning. Offline-capable. Starting at $15.
A garden sensor node is a small, connected device that continuously monitors environmental conditions around your plants. It measures soil moisture, air temperature, humidity, and light — then sends that data wirelessly to a central system for analysis and automation.
Think of sensor nodes as the "eyes and ears" of your smart garden. Without sensor data, garden automation is just a timer. With it, your system can make intelligent decisions: water only when soil is dry, skip watering before rain, and alert you when conditions threaten plant health.
PlantHub sensor nodes are built on the ESP32-C3 microcontroller — the same chip used in commercial IoT products. Each node includes four calibrated sensors, WiFi connectivity, and enough processing power to run automation rules locally when your internet drops.
Specifications
0–100% volumetric water content
Corrosion-resistant capacitive sensing (no exposed metal electrodes). Unlike resistive sensors that degrade within weeks in wet soil, capacitive probes last for years. Readings update every 30 seconds by default.
-40°C to 80°C · ±0.5°C accuracy
Measures ambient air temperature around your plants. PlantHub's AI uses this to detect frost risk, heat stress, and optimal growing windows for each plant species.
0–100% RH · ±2% accuracy
Critical for tropical plants, seedlings, and greenhouse growing. PlantHub monitors humidity trends and alerts you when levels drop below your plant's comfort zone.
1–65535 lux · 16-bit resolution
Measures actual light reaching your plants in lux. PlantHub uses light data to determine if plants are getting enough sun, and factors light levels into watering decisions — less water on cloudy days.
PlantHub sensor nodes follow a read → publish → analyze → act architecture designed for reliability and security:
ESP32-C3 → MQTT (mutual TLS) → AWS IoT Core → PlantHub AI → ESP32-C3
Sensor readings are collected by the ESP32-C3 at configurable intervals (default: 30 seconds). Data is published to AWS IoT Core over MQTT with mutual TLS authentication — each device has its own X.509 certificate, so no shared keys or passwords.
PlantHub's AI engine subscribes to incoming sensor data in real time via server-sent events (SSE). It evaluates readings against the plant's species profile, current weather forecasts, and historical trends. Decisions are compiled into lightweight rules and pushed back to the ESP32 node for local execution.
If connectivity drops, the node falls back to its last compiled ruleset. Your garden keeps running — watering schedules, threshold alerts, and safety limits all execute locally on the ESP32-C3 until the connection is restored.
Building your own ESP32 sensor node is a great learning project. But if you want a production-ready garden monitoring system without the setup overhead, here's how PlantHub nodes compare:
| Aspect | PlantHub Node | DIY ESP32 Build |
|---|---|---|
| Setup time | < 2 minutes | 2–8 hours |
| Total cost | From $15 (complete) | $8–30 (parts only) |
| Soldering required | None | Usually required |
| Firmware updates | OTA automatic | Manual USB flash |
| Cloud connectivity | Mutual TLS to AWS IoT | DIY MQTT setup |
| AI analysis | Built-in with 50+ plant profiles | Not included |
| Weather integration | 28-hour forecasts included | Custom API work |
| Security | Per-device X.509 certificates | Basic or none |
| Offline operation | AI-compiled ESP32 rules | Custom firmware |
| Support | Managed platform | Community forums |
The number of sensor nodes depends on your growing setup and how many distinct microclimates you want to monitor:
Each node operates independently with its own sensor array. PlantHub lets you organize nodes into zones — logical groups like "Herb Garden", "Tomato Bed", or "Greenhouse Bay 3" — and apply AI settings per zone. Add nodes as you grow.
Traditional ESP32 setups require flashing firmware, hard-coding WiFi credentials, and manually configuring MQTT endpoints. PlantHub eliminates all of that with plug-and-claim provisioning:
When you power on a new PlantHub sensor node, it generates a unique claim code. Enter that code in the PlantHub app, and the system automatically provisions the device with:
For greenhouse deployments, PlantHub supports admin claim codes that let you provision multiple nodes in bulk — no per-device setup required.
PlantHub sensor nodes give you production-grade garden monitoring without the DIY complexity. Learn more about the complete system:
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