Irrigation controller

irrigation_controller

Overview

This controller is used to remotely control a drip irrigation system.

It controls up to 3 irrigation zones and, optionally, a submersible pump.

Home Assistant controls the watering sequences:

• activation of the irrigation controller, programmable start time of the irrigation sequence
• behavior of each zone (availability and watering duration)

Features

On the irrigation controller

• water inlet: one 3/4" connection, on the right side
• water outlets: 1, 2, or 3 × 3/4" connections, facing downward
• for each outlet:
  • a manual control button (all 3 valves can be opened at the same time)
  • a LED that lights up when the valve is open
• a safety timeout turns off the valves after EV_timeout minutes of activation
• the status LED blinks when WiFi is connected
• the controller is powered from 230 V AC

In Home Assistant

A button makes the controller active (watering according to the zone parameters) or inactive (no watering).

Start time: HH:MM [0:00 to 23:59], when the watering sequence shall start.

The behavior of each zone is defined in Home Assistant with the following parameters:

• availability: true if the zone is used, false if it is not used
• days of week: frequency of watering (to be added)
• duration: watering duration in minutes [1 to 15]
• frequency: 1 cycle (every 24h), 2 cycles (every 12h), 3 cycles (every 6h) (to be added)
• a button to manually operate the zone (immediate start on the 1st push, immediate stop on the 2nd push)
• rain sensor: disables the watering sequence while it is raining (to be added)

Sequence definition: at the start time, zone 1 is operated for the given duration if it is activated, then zone 2, then zone 3.

Hardware

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Electronics

Schematic & PCB designed using KiCad 9

• Microcontroller: Seeed Studio XIAO ESP32-C3
• 12 V solenoid valve control: power MOSFET IRFZ24N (55 V, 17 A)
• Submersible pump control: 230 V Triac BT136-600

Final design PCB dimensions 148 × 61 mm, 4 mounting holes (141.4 × 45 mm)

Various configurations are available a) 2 valves + 1 pump
The D5 LED (= TRIAC is active) is optional.

b) 3 valves, no pump
Yet to come

Hydraulic

• Inlet: 3/4" (20/27) for an automatic garden connection
• Outlet: 3/4" (20/27) for an automatic garden connection
• solenoid valves: 12 V DC, NC, 0.02 - 0.8 MPa, 1/2" (15/21) solenoid valve, from a washing machine
• 14 mm copper pipes

Firmware

• The ESP32 module manages
  • the GPIOs
  • a script to drive the solenoid valves and the submersible pump
  • a safety timeout to stop watering in case HA is disconnected during a watering sequence
• HA manages the irrigation sequences and the manual control through a card in the "garden" dashboard

ESPHome firmware

binary sensor:

• SW3, SW2, SW1 (must be high at boot): manual command on the device
• ev1_active, ev2_active: provide HA with the actual status of the solenoid valves

switch: ON/OFF command

• EV1, EV2, EV3: commands for the 3 solenoid valves
• pump control: submersible pump command

output:

• status LED (HIGH side command)

sensor:

• WiFi RSSI in dBm

button:

• 3 virtual buttons to manually control EV1, EV2 and EV3 in HA

wifi:

• automatically connects to any of the 3 WiFi routers in the home

light: (The binary light platform creates a simple ON/OFF-only light from a binary output component.)

• led_status: blinks the status LED according to LED_ON (100 ms) and LED_OFF (4900 ms)

script:

• toggle_EV1, toggle_EV2, toggle_EV3: turn the given solenoid valve on and off; turn on the submersible pump when at least one valve is on, and turn it off when all valves are off; launch the safety timeout
• valves_safety_timeout: turns off every command after EV_timeout (typically 30 min)

Home Assistant configuration

All the elements linked to the irrigation controller are found under the label "irrigation".

Device

• add "irrigation_ctl1" under Settings → Devices & Services → ESPHome

Entities

The actionable entities are:

• EVi command: executes the script toggle_EVi
• pump: switch_toggle pump
• EVi: switch_toggle solenoid valve i

Helpers

• common to all zones:
  • irrigation_auto: enables the automatic watering program
  • irrigation_heure_debut (watering start time): the time at which watering starts
• for each zone (i = 1, 2 or 3):
  • irrigation_active_zonei: enables the watering program on zone i
  • irrigation_duree_zonei (watering duration zonei): the watering duration of zone i

Script

• lancer_goutteAgoutte_1 (run drip irrigation): executes commande_EVi if irrigation_active_zonei is true, for the duration irrigation_duree_zonei

Automation

• Démarrage irrigation (Start irrigation): at irrigation_heure_debut, executes the script lancer_goutteAgoutte_1 if irrigation_auto is set to true

Dashboard

a) 2 valves version, french language

• Mode Auto ('Auto mode'): makes the controller active (watering according to the zone parameters) or inactive (no watering)
• Heure Début ('Start time'): the start time of the watering sequence
• Zone 1, Zone 2: a single click manually starts the watering of the selected zone. A second click stops the watering. While watering is on, the icon turns red.
• Activé/desactivé ('Enabled/Disabled'): if enabled, the zone is included in the watering sequence
• Duration: automatic watering duration, from 1 min to 15 min