Technical detail

Architecture, surge protection, and the engineering choices behind the box.

For engineers, irrigation distributors, certification reviewers, and anyone evaluating HydroIQ against a competing system. The home page is for growers; this page is for the people they'd ask before specifying it.

System architecture

From soil probe to dashboard, every link.

The Controller speaks RS485 Modbus to the soil probes, sub-GHz LoRa to the Hydro Nodes, and standard TLS to the cloud. Schedules and dosing run locally; the cloud is additive.

SOIL                  CONTROLLER                  CLOUD                 USER
══════                ════════════                ═════                 ════

[Probe Z1] ──┐
[Probe Z2] ──┤
[Probe Z3] ──┼─ RS485 ──▶ [Hydro                ┌──▶ [Schedule    ──▶ [Dashboard]
[Probe Z4] ──┤ Modbus     Controller] ──TLS──┤   optimizer]
[Probe Z5] ──┘            │                    │   [Camera vision  ──▶ [Mobile app]
                          │                    │   analysis]
                          ├──▶ [Latching       │   [Per-zone       ──▶ [Multi-site
[Valve Z1] ──┐  9V DC     │     valve driver]  │   learning]            portal]
[Valve Z2] ──┼◀──────────┘                    │
[Valve Z3] ──┘            │                    └──▶ [Data licensing
                          │                         opt-in tier]
[WX station] ──┐          │
[Camera]      ─┼─ UART/I2C─┤
[Fertigation] ─┘            │
                          │
[Hydro Node 1] ────┐      │
[Hydro Node 2] ──── sub-GHz LoRa
[Hydro Node N] ────┘ (long range, low power)

Local-first: irrigation + fertigation run without internet.
Cloud is additive (remote access, AI learning, multi-site).

Local-first guarantee: if the cloud is unreachable, the Controller continues running its last-known schedule and fertigation rules from non-volatile storage. A 24-hour cloud outage triggers an on-board buzzer alert at the unit; on the next reconnect the Controller logs the outage to the cloud history and the owner is notified via email and the app. Field-remote beds reach the Controller over sub-GHz LoRa via the Hydro Node accessory — the Node, in turn, is battery- and solar-powered and operates independently of any outside connectivity.

Surge protection

Earth-free surge protection. No ground rod needed.

Most outdoor irrigation controllers require an earth ground rod installed at the customer site — both for code and for surge survival. HydroIQ doesn't.

The problem

Lightning surges enter outdoor irrigation systems through any external port — power, valve wires, sensor leads, comms. Standard MOV/GDT-based protection requires a low-impedance earth reference; without one, the surge has nowhere to go and clamps potential rises across the protected components. Installers either drive a ground rod (cost, code complexity, soil resistivity issues), skip protection (and replace boards every few years), or charge accordingly.

Our approach

External-facing ports are classified into protection groups by voltage polarity, current direction, cable exposure, and downstream component voltage rating. Each group gets a topology selected from four options (parallel TVS array, two-stage TVS-inductor-TVS, blocking semiconductor with cable-side TVS, coordination resistor with inter-line clamp). All reference a unified floating local ground bus with no galvanic connection to earth. During a surge, the entire bus potential rises uniformly — preventing the differential voltage stress that destroys components.

Test compliance

  • IEC 61000-4-5 Class 4 (4 kV) — no earth required
  • FCC Part 15B (planned 2026 cert)
  • UL 60730 (controls for irrigation, planned 2026)
  • CE / UKCA (planned Year 2 for EU expansion)

Provisional patent application filed: "Earth-Free Multi-Group Surge Protection System for Sealed Electronic Enclosures." Specifications available under NDA for distribution partners.

Bus + isolation

Industrial RS485 + galvanic isolation where it matters.

Hydro Controller (line-powered)

Isolated RS485 transceivers (THVD1426) on every sensor and bus port. Galvanic isolation rated for UL/CE per-port. Field ground faults stay in the field.

Hydro Node (battery-floating)

Non-isolated transceivers (cost + power optimization) — safe because the Node is battery-floating and physically isolated from the AC mains. Different operating constraint, different solution.

Three-family connectors

GX16 (power), M12 (sensor bus), M8 (signal) — physically non-mateable across families. Eliminates the most common field-install error mode (cross-mating power into a sensor port).