🌿 Smart Irrigation System — Functional Requirements (v2)

1. System Purpose

The system SHALL automatically monitor soil moisture across multiple plant beds, make localized watering decisions per bed using averaged sensor data, and provide real-time monitoring and control via a centralized Raspberry Pi web server.

2. System Architecture

2.1 Distributed Bed Nodes

Each plant bed SHALL operate as an independent embedded node using an ESP32 microcontroller.

Each bed node SHALL include:

1 × ESP32

5 × soil moisture sensors

1 × water control actuator (relay + valve or pump)

WiFi communication module (built-in)

2.2 Central Server

The system SHALL include a Raspberry Pi running a local web server that:

Receives sensor data from all bed nodes

Stores and processes incoming data

Hosts a real-time monitoring dashboard

Provides system-wide visibility

3. Bed Node Functional Requirements

3.1 Sensor Data Acquisition

Each bed node SHALL:

Read moisture values from 5 soil sensors

Sample sensors at a fixed interval (configurable)

Validate readings to remove invalid or out-of-range values

3.2 Moisture Calculation

Each bed node SHALL:

Compute the arithmetic mean of all 5 sensor readings:

Use the computed average as the bed moisture indicator

3.3 Watering Decision Logic

Each bed node SHALL:

Compare average moisture against a configurable threshold

If average indicates dryness:

Activate water valve for a defined duration

If moisture is sufficient:

Keep valve OFF

3.4 Watering Safety Controls

Each bed node SHALL:

Enforce a cooldown period between watering cycles

Prevent continuous activation beyond maximum duration

Default valve state SHALL be OFF on startup or failure

4. Communication Requirements

4.1 Network Connectivity

Each ESP32 node SHALL:

Connect to WiFi automatically on boot

Reconnect if connection is lost

Continue local irrigation logic without network dependency

4.2 Data Transmission

Each node SHALL send periodic updates to the Raspberry Pi server including:

Bed identifier

Timestamp (ISO 8601)

Individual sensor readings

Average moisture value

Valve state

Signal strength (optional)

Example payload:

{

"bed_id": "bed_1",

"timestamp": "2026-04-09T12:00:00Z",

"sensors": [410, 395, 480, 420, 390],

"average": 419,

"valve_state": "OFF",

"rssi": -60

}

4.3 Communication Protocol

The system SHALL support:

HTTP POST (primary implementation)

Optional MQTT compatibility for scaling

5. Raspberry Pi Server Requirements

5.1 Data Ingestion

The server SHALL:

Accept incoming data from all bed nodes

Validate payload structure

Associate data with correct bed ID

5.2 Data Storage

The server MAY:

Store historical readings per bed

Maintain time-series logs for analysis

5.3 Real-Time Processing

The server SHALL:

Maintain latest state per bed

Update dashboard data within near real-time latency

6. Web Dashboard Requirements

6.1 System Overview View

The dashboard SHALL display:

All beds in a grid layout

Current moisture average per bed

Valve state (ON/OFF)

Last update timestamp

6.2 Bed Detail View

Each bed SHALL have a detail panel showing:

Individual sensor values

Average moisture trend

Watering history

Connection status

6.3 Real-Time Updates

The dashboard SHALL:

Update automatically without manual refresh

Reflect changes within seconds of ESP32 updates

7. Configuration Requirements

7.1 Per-Bed Configuration

Each bed SHALL support:

Moisture threshold value

Watering duration

Sampling interval

Cooldown period

7.2 System Configuration

The system SHALL allow configuration of:

WiFi credentials

Server endpoint

Global update interval defaults

8. Reliability Requirements

The system SHALL:

Continue irrigation logic if server becomes unavailable

Recover automatically from network failure

Default to safe OFF state for all actuators on reboot

Prevent stuck-on valve conditions using timeout safeguards

9. Power Requirements

The system SHALL:

Use separate power supply for actuators (pump/valves)

Ensure ESP32 is not directly powering high-load components

Maintain stable 5V regulated supply for controllers

10. System Behavior Summary

Each bed node SHALL function as:

an autonomous moisture monitoring and watering controller

The Raspberry Pi SHALL function as:

a centralized monitoring, logging, and visualization system

🧸 Final Shape of Your System

You’ve basically built:

🧠 distributed embedded control (ESP32 beds)

💧 local decision-making (averaging logic)

🌐 centralized observability (Raspberry Pi dashboard)

📡 live telemetry pipeline (WiFi data streaming

Hardware

Moisture sensors (5 pack) https://a.co/d/08jgp9i0 -> 12.99$

Esp 32 (1 pack) https://a.co/d/0gWkgj1d -> 10$

Electronic waterproof box://a.co/d/0bZPKaHF -> 15$

Proto bord https://a.co/d/084GUDtd -> 10$

Soldering iron kit https://a.co/d/0blNSt7l -> 27$

Boost converter https://a.co/d/06VqAMKu -> 5$

USB c pd https://a.co/d/0aFaKluF -> 8$

Solid core wire https://a.co/d/0d2wdwJW -> 13$

3 conductor wire https://a.co/d/0aJJDiKh -> 14$

Battery bank https://a.co/d/0cTmBX93 -> 24$

Water solidnoid https://a.co/d/0fcChfRU -> 41$

Raspi 3 https://a.co/d/0iV00K1j -> 90$

Hose adapter https://a.co/d/08PHq3U3 -> 16$

Relay bord https://a.co/d/00JKLzu1 -> 6$

Irrigation hose https://a.co/d/0ir0gQr8 -> 18$

Terminal block https://a.co/d/09clhrCy -> 6$

Volt meter https://a.co/d/01X2x7zS -> 15$

Solar Panel Amazon.com : FUTUREZEN Solar Panel for Security Camera, 10W Solar Charger with DC 5.5x2.1mm, USB-C & Micro USB Port, IP66 Waterproof, 360° Adjustable Mount, 7.2FT Cable : Patio, Lawn & Garden -> 39.99$

Continuous current draw need and total energy needed

Idle current ~0.08 – 0.1A (80–100 mA) at 12V

Solenoid active current 0.5–1A @ 12V

I want to start with one garden bed as a prototype for my smart irrigation system. I’ll use it as a dev setup to test everything, and once it’s working reliably, I’ll expand it to the rest.”

Tracking the sun exposure of plants