Smart Irrigation Bridge¶

This guide shows how to use ws_core's ET₀ sensors as the input for the Smart Irrigation integration.

Smart Irrigation uses ET₀ to calculate how much to irrigate each day, accounting for rainfall. ws_core provides the ET₀ value; Smart Irrigation decides the watering schedule.

Prerequisites¶

Weather Station Core installed and configured
Smart Irrigation installed via HACS
A solar radiation sensor mapped in ws_core (for Penman-Monteith ET₀) OR acceptance of the Hargreaves-Samani approximation

Which ET₀ sensor to use¶

Use sensor.ws_et0_pm_daily if you have a solar radiation sensor mapped in ws_core. This uses FAO-56 Penman-Monteith with ±5-10% accuracy.

Use sensor.ws_et0_daily if you do not have a solar radiation sensor. This uses Hargreaves-Samani with ±15-20% accuracy. Adequate for most residential irrigation scheduling.

Step 1: Configure Smart Irrigation with a manual ET₀ source¶

In Smart Irrigation configuration, when prompted for the ET₀ source, choose Manual / Custom sensor (the exact option name may vary by Smart Irrigation version).

Step 2: Map the ET₀ entity¶

Set the ET₀ entity to: - Preferred: sensor.ws_et0_pm_daily - Fallback: sensor.ws_et0_daily

Set the unit to mm (millimetres per day).

Step 3: Map the rainfall entity¶

Smart Irrigation also needs daily rainfall. Map: - sensor.ws_rain_today for today's accumulated rainfall

This sensor resets at local midnight and accumulates rain from your physical gauge. The unit is mm.

Step 4: Verify the values¶

After one full day of operation, check that: 1. sensor.ws_et0_pm_daily (or ws_et0_daily) shows a non-zero value 2. sensor.ws_rain_today shows today's rainfall correctly 3. Smart Irrigation shows a sensible irrigation time calculation for your zone

Typical Penman-Monteith ET₀ values: - Temperate summer: 3-6 mm/day - Mediterranean summer: 6-9 mm/day - Arid summer: 8-12 mm/day

Step 5: Set up the irrigation skip automation¶

Use the ws_core irrigation_rain_skip.yaml blueprint (see Blueprints) to automatically skip irrigation when: - Rain accumulated in the past 24h exceeds a threshold, OR - Rain is expected in the next hour (binary_sensor.ws_rain_expected_1h is On)

Sample automation (without blueprint)¶

alias: "Irrigation: rain skip"
trigger:
  - platform: state
    entity_id: binary_sensor.ws_rain_expected_1h
    to: "on"
  - platform: numeric_state
    entity_id: sensor.ws_rain_last_24h
    above: 10
action:
  - service: switch.turn_off
    target:
      entity_id: switch.smart_irrigation_<zone_name>

Replace <zone_name> with your Smart Irrigation zone switch entity ID.

Proposed Smart Irrigation documentation PR¶

A PR proposal for the Smart Irrigation documentation site is saved at docs/promotion/smart_irrigation_docs_pr.md. This proposes adding ws_core as a documented ET₀ source in Smart Irrigation's official docs.