Having just had a day without power, and then going round the site to check everything came back online correctly (including services such as water pumps, septic systems, freezers etc) I started thinking again about our wastewater system.
This is a Taylex envirocycle (septic tank + air blower + submersible pump in the final stage to deliver the effluent to 200m+ of dripper lines in a field). The "smarts" aren't really much - The power from the main switchboard comes in to a single outlet that has a 12v plugpack that powers the PCB, and on to a double outlet (with an overload trip) that powers an air blower + submersible pump. The blower runs 24/7 and has a pressure switch going to the PCB, and the pump cycles independently when it's float switch rises. There's a high-level float switch that triggers an alarm on the PCB, and that's about it.
Something that integrates with Home Assistant and tells me:
- system power OK
- Binary sensor for Air pressure trip
- Binary sensor for high level alarm
- Indication of when the discharge pump's running
The obvious one is what about updates? ANY network connected device presents an attack surface if not maintained. Sure, I'm likely to keep stuff ticking over, but what about $future_owners? obvs, I won't be using a cloud service for any of this and hardware will be 'input only' so it won't affect the running of the system. What's the design lifetime for one of these units anyway? 20-30 years?