A small always-on machine was needed to poll every device, hold the CO₂ control loop, and publish the record, without becoming something the tank depends on to stay alive.
What I've learned
·Everything safety-critical belongs on the controller; the Pi is for orchestration and record-keeping.
·An external watchdog that runs off the Pi is necessary, since it catches the failures the Pi itself cannot report.
Installation
Not yet documented.
Configuration
·Runs Pearl, the self-hosted dashboard and automation layer
·Polls the controller, filter and doser, writing to a time-series store
·Holds the CO₂ control loop against the morning baseline
·Captures an hourly growth frame while the light is on
Maintenance
Not yet documented.
Known limitations
Not yet documented. Absence here means nothing has been written down, not that there are none.
Controller integration
Polls the controller, filter and doser; holds the CO₂ loop; writes the time-series record. Nothing safety-critical depends on it.
Maintenance history
No service dates recorded yet. Scheduled replacement applies to consumables; this item is tracked by condition instead.