Project Context

This project implements a data acquisition (DAQ) system for an aquaponic farm: the *Ferme Aquaponique du Pays de Gex*, located in the Pays de Gex, France.

Website: https://www.lafermeaquaponique.com/

Users

• Customers are aquaponic farmers.
• Assume no higher IT sophistication than the average person.
• Assume deep expertise in aquaponic farm design and operation.

Architecture

All hosts are on the same farm LAN.

• 4 DAQ nodes: Raspberry Pi 2W units, each with 1 Atlas Scientific USB EZO carrier board + 1 probe
• 1 DAQ hub: Raspberry Pi 5 (MQTT broker)
• 1 DAQ recorder: remote VPS (persists MQTT messages to SQLite)
• 1 Dashboard: same VPS (Mojolicious web app)

Probes: pH, EC, Dissolved Oxygen, ORP (all Atlas Scientific).

Messaging

• DAQ nodes publish readings over MQTT.
• DAQ hub acts as MQTT broker.
• DAQ recorder persists all MQTT messages to a relational database.
• Topics: `fapg/daq/<probe>/<node>/reading`
• Schema: `fapg.daq.reading.v1`
• Probe keys are always lowercase: `ph`, `do`, `orp`, `ec`.

OS Versions

| Host | OS | Version | |--------------|----------------------|----------| | DAQ nodes | Raspberry Pi OS Lite | Trixie | | DAQ hub | Raspberry Pi OS Lite | Trixie | | DAQ recorder | Debian 11 | Bullseye | | Dev machine | Gentoo | latest |