LibrePiLogger: Hardware Design Files, Software, and Deployment Scripts

This repository combines the hardware design files, software library, and deployment scripts for LibrePiLogger, an open-source, low-cost data logging platform built around the Raspberry Pi for long-term environmental monitoring using Modbus sensors. The platform was developed at the Institute for Modeling Hydraulic and Environmental Systems (IWS), University of Stuttgart, and has been deployed for continuous CO₂ and ²²²Rn monitoring in karst environments.

The hardware design files describe two configurations assembled entirely from off-the-shelf components (Raspberry Pi, RS485 interface, power supply) at a total cost of 54–63 €. Sensor communication is handled by AtmosPyre, a Python library that abstracts Modbus communication over RS485 with built-in support for CO₂ and ²²²Rn sensors; new instruments can be added via a lightweight driver of approximately 100 lines. Deployment across one or many units is automated by senso-pi, an Ansible-based toolkit that handles hardware configuration, dependency installation, and systemd service setup for RS485 sensors using AtmosPyre. Data is logged to timestamped CSV files with JSON metadata.

Files in this repository:

• wiring_diagram_usb.pdf / wiring_diagram_usb.svg: wiring diagram for the maximal setup (Raspberry Pi 4 with USB-to-RS485 converter).
• wiring_diagram_hat.pdf / wiring_diagram_hat.svg: wiring diagram for the minimal setup (Raspberry Pi Zero with RS485 CAN HAT).
• atmospyre-v1.0.1.zip: source archive of the AtmosPyre Python library (Modbus sensor communication) at release v1.0.1.
• senso-pi-v1.0.1.zip: source archive of the senso-pi Ansible deployment toolkit at release v1.0.1.

The AtmosPyre and senso-pi archives are frozen snapshots of a tagged release. For the latest development version, bug fixes, and updates, use the corresponding Git repositories instead: AtmosPyre at gitlab.com/libre-pilogger/atmospyre and senso-pi at gitlab.com/libre-pilogger/senso-pi.

This repository accompanies the manuscript "A Flexible Raspberry Pi-Based Data Logger Platform for Modbus Sensors with Ansible Deployment", submitted to HardwareX.