How IoT Monitoring Changed Vessel Management
Building low-power ESP32 sensor networks and 915MHz LoRa gateways to stream real-time bilge cycle, battery voltage, and drift alerts.
Leaving a vessel unattended on a mooring or dock comes with background anxiety. Did the bilge pump float switch stick? Are the house batteries maintaining voltage? Has the anchor mooring line slipped? Traditionally, solving this required expensive subscription-based satellite trackers.
We took a different approach for our fleet. We built a local 915MHz LoRa mesh network linked to low-power ESP32 edge sensor nodes, routing data locally without expensive cellular contracts.
ESP32 Edge Sensor Nodes
Each node is housed in a waterproof 3D-printed ASA enclosure. The nodes are built around the ESP32 microchip, utilizing its deep-sleep mode to run for up to six months on a single lithium battery:
- Bilge Monitors: Non-contact liquid level sensors track bilge water levels. Current-sensing loops monitor bilge pump activation cycles, logging pump duty profiles.
- Battery Monitors: Voltage dividers track battery cells, reporting voltages via LoRa packets every ten minutes.
- Mooring Monitors: GPS receivers trigger local alerts if the vessel leaves a defined mooring boundary box.
LoRa to Gateway Ingestion
The sensor nodes transmit telemetry packets using the 915MHz LoRa frequency band. A master gateway node, located in the cabin, ingests these packets and formats them as standard Signal K payloads.
The gateway processes data locally, triggering high-decibel cockpit alarms or sending low-bandwidth alerts through our Starlink telemetry bridge when satellite data channels are active.