DxP Data Logger Hardware (LoRa + Distributed Sensor Probes Interface)

This repository only contains the hardware for the DxP (Distributed sensor Profiling) data logger (i.e., the “logger / base station” main board that connects to a DxP sensor probe via a connector.

The sensor probe / sensor-array board designs for DxP probes are released in a separate repository.

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Hardware overview

Designed for low-power, distributed environmental sensing deployments using the system concept from:

• Wielandt et al., “TDD LoRa and Delta Encoding in Low-Power Networks of Environmental Sensor Arrays for Temperature and Deformation Monitoring” (2023)

Main logger board capabilities:

• LoRa modem: RFM95W (single-channel LoRa)
• Wireless SoC: Nordic nRF52832 (BLE capable)
• Timekeeping: PCF2129AT RTC
• On-board storage: 4 MB SPI flash (data buffering)
• Power: designed for 2× AA operation (1.8 V – 3.6 V range); includes load switching (e.g., TPS22919) to reduce sleep power
• Sensor/probe interface: I2C to connect to distributed sensor probes (supports long arrays through an address bit shift register on the sensor probe).
• Micro SD card slot with load switch for extra storage (e.g., large sensor datasets) and/or for base-station workflows to store data from multiple devices in the network.

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Repository contents

KiCad design files (schematic / PCB)

• loggerhw_v5.0.sch
• loggerhw_v5.0.kicad_pcb
• loggerhw_v5.0.kicad_pro
• loggerhw_v5.0.kicad_prl
• loggerhw_v5.0.pro

KiCad libraries

• symbol/
• footprints/
• fp-lib-table
• fp-info-cache/
• sym-lib-table
• loggerhw_v5.0-cache.lib

Production / fabrication exports

• fab/

Documentation

• README.md
• LICENSE.md
• users.md