Automated Plant Watering System
Automates plant watering based on soil moisture and provides monitoring via a mobile application
Author: Manolache Alexandra Claudia
GitHub Project Link: https://github.com/UPB-PMRust-Students/proiect-alexandra33312
Description
This project automates plant watering using a Raspberry Pi Pico W microcontroller and a mobile application for remote monitoring and control. A soil moisture sensor detects the moisture level, and when the soil becomes too dry, the Pico W activates a relay module that powers a water pump. The mobile app communicates with the Pico W via a simple REST API, displaying real-time data and allowing manual watering from anywhere.
Motivation
I chose this project to optimize water usage and ensure plant health by eliminating the risk of overwatering or underwatering. Integrating a mobile app offers maximum flexibility and an intuitive way to monitor soil conditions and watering activity. Additionally, the system can be scheduled to water at specific time intervals.
Architecture
The system architecture is divided into four main logical components:
Sensing Layer : Soil Moisture Sensor Module: Reads analog moisture values from the YL-69 sensor and converts them into digital readings via the Pico W’s ADC.
Control Layer - Raspberry Pi Pico W: Hosts the core logic, compares sensor readings against thresholds, and decides when to activate the irrigation. Exposes a REST API over Wi-Fi for status reporting and remote control.
Actuation Layer- Relay & Pump Module: Receives digital control signals from the Pico W GPIO to switch the relay, which powers the water pump. Feedback Indicators: LED and buzzer provide local visual and audible status alerts (e.g., watering in progress, errors).
Presentation & Management Layer - Mobile Application (Android/iOS): Polls the Pico W REST API to display real-time moisture data, pump status, and watering history. Allows manual triggering of irrigation via POST requests.
Data Flow & Integration :
- The sensor module measures soil moisture and sends the analog signal to the Pico W.
- The control logic on the Pico W evaluates the reading and, if dry, activates the relay to power the pump.
- The pump waters the plants, and the Pico W logs the event.
- The Pico W REST API provides endpoints such as /status (GET moisture, pump state) and /water (POST to trigger watering).
- The mobile app periodically polls /status and displays data in the UI; a manual button invokes /water to start irrigation on demand.
Schematics
Log
Week 5 - 11 May
Set up development environment for Raspberry Pi Pico W (VS Code + Pico SDK) Researched YL‑69 soil moisture sensor and tested basic analog readings on Pico W Drew initial block diagram of system architecture Make Kicad schematics
Week 12 - 18 May
Calibrated moisture sensor thresholds (dry vs. wet) through voltage measurements Implemented and tested ADC reading code on Pico W Integrated 5 V relay module; wrote GPIO control routines to switch pump on/off.
Week 19 - 25 May
Developed simple REST API on Pico W (endpoints /status and /water) Created basic KiCad schematic for sensor, relay, and power connections Began prototyping mobile app UI in React Native (status screen and manual control button)
Hardware
The following hardware components are used in this project to sense soil moisture, control irrigation, and provide power and feedback: Raspberry Pi Pico W: Main microcontroller with integrated Wi‑Fi and 12‑bit ADC (for sensor reading) YL‑69 Soil Moisture Sensor Module: Analog sensor probes + comparator module for measuring soil moisture 5 V Relay Module: Drives the water pump by switching its power on/off via GPIO signal DC Water Pump (3–6 V): Pumps water through tubing to irrigate plants 6 mm Silicone Tubing: Carries water from the pump to the plant pots 10 kΩ Resistor: Forms a voltage divider with the YL‑69 sensor for stable ADC readings LED (Red/Green): Visual feedback for system status (e.g., watering, idle, error) 5V Buzzer: Audible alert for errors or watering start/stop Jumper Wires & Breadboard: Prototyping and connections between components 5V 3A Power Supply: Powers the relay module and pump; Pico W is powered via the same supply (through breadboard power lines)
Schematics
Place your KiCAD schematics here
[Work in progress...]
Bill of Materials
| Device | Usage | Price |
|---|---|---|
| Raspberry Pi Pico W | Main microcontroller | 70x2 |
| Soil Moisture Senzor | Soil moisture measurement | 3.99 |
| 5V Relay Module | Switches pump power for | 4.99 |
| irrigation | ||
| DC Water Pump (3–6V) | Pumps water through tubing | 16 |
| 6 mm Silicone Tubing | Transports water to plant | 10 |
| 10 kΩ Resistor | Voltage divider for sensor | 1 |
| Jumper Wires | Connections between components | 12 |
| Breadboard | Prototyping platform | 10 |
| 5V 3A Power Supply | Powers Pico W and pump | 24 |
| Red/Green LED | Visual feedback indicator | 1 |
| 5V Buzzer | Audible alert | 1 |
Soil Moisture Senzor https://www.optimusdigital.ro/ro/senzori-senzori-de-umiditate/73-senzor-de-umiditate-a-solului.html?search_query=umiditate&results=165
5V Relay Module https://www.optimusdigital.ro/ro/cautare?controller=search&orderby=position&orderway=desc&search_query=5v+releu&submit_search=
DC Water Pump (3–6V) https://www.emag.ro/pompa-de-apa-3-6v-cl88/pd/D91Z5JBBM/#reviews-section
6 mm Silicone Tubing https://claumarpescar.ro/tub-siliconic-mostiro-1m-0.6mm.html?srsltid=AfmBOorzXBO0eFCGJUn9feYSHYxty-69NSNSLf_W9DOd_fCkD1tnU4bg
Jumper Wires https://www.optimusdigital.ro/ro/fire-fire-mufate/891-set-fire-tata-tata-10p-30-cm.html?search_query=fire&results=429 https://www.optimusdigital.ro/ro/toate-produsele/877-set-fire-mama-tata-40p-15-cm.html?search_query=Fire+Colorate+Mama-Tata+%2840p%29&results=5
5V 3A Power Supply https://www.emag.ro/sursa-de-alimentare-5v-3a-pa5-3/pd/DJYZ6TMBM/
Red/Green LED https://www.optimusdigital.ro/ro/kituri/9698-kit-plusivo-pi-4-fara-placa-i-fara-card.html?search_query=KIT&results=324
Software
Firmware (Rust / Pico W)
| Library | Description | Usage |
|---|---|---|
rp2040-hal | Hardware Abstraction Layer pentru RP2040 | GPIO, ADC, PWM, UART and I²C control |
embassy + embassy-rp | Async executor & suport specific RP2040 | Concurrent task scheduling |
embedded-hal | Standard HAL traits | Unified API for GPIO/ADC interactions |
embedded-graphics | Grafica 2D pe display | Drawing text and icons on the ST7789 display |
st7789 | Driver display ST7789 | Low-level control of the SPI-driven display |
defmt | Framework de logging eficient | Lightweight debug output over serial/USB |
serde + serde_json | Serializare JSON | JSON parsing and formatting for the REST API |
Mobile APP
| Library | Description | Usage |
|---|---|---|
react-native | Cross-platform mobile framework | Builds Android & iOS user interfaces |
react-navigation | Routing and navigation | Screen and stack management |
axios | Promise-based HTTP client | Fetching GET /status and POST /water |
victory-native | Charting library | Rendering moisture history graphs |
react-native-push-notification | Push notifications | Alerts when moisture is below critical level |
Links
https://datasheets.raspberrypi.com/picow/pico-2-w-datasheet.pdf