SCADA-project/docs/decisions/0001-initial-architecture.md

ADR 0001: Initial Architecture Decisions

Date: 2026-06-19 Status: Accepted

Context

We need a monitoring system for small water systems that is affordable, low-egress, and usable by both non-technical owners and professional operators.

Decision

We will use a hybrid edge + cloud architecture with:

• Raspberry Pi 5 edge devices
• Tiered telemetry (compressed healthy summaries + rich alert payloads)
• Monitored Objects as the core abstraction
• Hybrid AI (small edge models + larger cloud models)
• Multi-tenant web application with role-based access

Consequences

• Strong emphasis on local processing to control data costs
• More complex initial onboarding (AI interview + camera mapping)
• Clear separation between Basic (owner) and Advanced (operator) dashboard views

Alternatives Considered

• Pure cloud SCADA (too expensive for small systems)
• Fully on-prem with no cloud (loses multi-system operator view and easier updates)