Version: ACS CC

Mini Smart Home

A tiny Rust-powered smart house that senses, blinks, and moves — just like a real one, but way cooler.😁

info

Author: Iordache Ioana-Diana
GitHub Project Link: https://github.com/UPB-PMRust-Students/proiect-ioanaior

Description

This project simulates a miniature smart home environment focused on energy-efficiency, automation, and comfort. Features include humidity monitoring for rain detection, an automatic window system, secure keypad-controlled door access, and visual feedback via an LCD and a high-power LED.

Motivation

I find it fascinating how sensors can interact with the environment and create real-life automation scenarios. I wanted to work on a project that’s both educational and fun, while also touching on concepts related to green homes, security, and interactivity. The idea of a miniature smart home felt like a great fit for demonstrating embedded programming in Rust. That is why I decided to create a small-scale model that could be both a learning experience and a nice gadget.😊

On a more personal note, I have a younger brother who’s been really into robots and home automation ever since we started tinkering with Arduino kits together. He’s always curious about how things work, and this project got him genuinely excited when he found out I was doing something like this in university. It’s been a great way to share the experience with him too; and honestly, seeing that kind of enthusiasm around something I build is extra motivation to make it work.

Architecture

The final system will include modules for:

Environment sensing:
- Analog humidity sensor (KS0203)
- Rain detection based on humidity threshold
Output feedback: LCD 1602 with I2C, for showing system status ("RAIN", "SUN", "UNLOCKED")
Actuators: Two servo motors: one for window control, one for door access
Input system: 4x4 button matrix keypad for entering an unlock code
Indicators: One high-power LED (on/off status display)
Optional modules: motion or gas sensors for enhanced interactivity and safety

Log

Week 21 – 27 April
Reviewed previously owned components (sensors, display, servo motors) to assess reusability for the project. Placed an order for a Raspberry Pi Pico 2 W as the main controller board. Researched compatibility and pin availability for each part to ensure smooth integration.
Week 28 April – 4 May
Drafted the initial project documentation. Defined the scope, motivation, and key goals. Outlined the planned system architecture and reviewed optional extensions. Started organizing the hardware list and validating available Rust crates for each module.
Week 5 – 11 May
Placed an order for a second Raspberry Pi Pico 2 W to use it for debugging.

Initially tested the DHT sensor but discovered that no compatible crate worked properly with the lab-provided Cargo.toml. As a workaround, I replaced it with a Keyestudio KS0203 Steam Sensor, an analog humidity sensor that turned out to be easier to interface with. I later converted its raw analog output into percentage values for better readability and user-friendliness on the display.

I also connected a 1602 I2C LCD, which dynamically displays either "RAINY" or "DRY", depending on the humidity threshold. This condition will eventually control the window via a servo motor.

In parallel, I integrated a 4x4 button matrix which now works as a basic security system: a 4-digit code must be entered correctly. If valid, the LCD shows "UNLOCKED", and this will be used later to activate the door’s servo motor.
Week 12 – 18 May
Finalized the control logic for both servos (door and window), linking them to sensor inputs and keypad status.

Initially, I attempted to use a WS2812 RGB LED module for visual feedback, but due to limitations in Rust crate support and stability issues, I opted for a simpler and more robust solution: a 3W High Power LED module. To manage it, I implemented a lightweight RgbLed abstraction that mimics PWM behavior using basic GPIO toggling. While it doesn’t support full-spectrum control, it serves well for status indication and general on/off signaling.

Additionally, I started researching on how to integrate a solar panel for charging an external battery. I finally managed to power the module using the Battery Power Module with Solar Port, connected to a 4.2V Li-ion battery and a small solar panel. If the battery and panel provide enough power, I’ll also be able to connect other parts of the system to the same power source in the future. It’s a nice step towards making the whole setup more independent and possibly usable outdoors without needing a wired power supply.

I also started building a frame to integrate the hardware - basically a small “house.” I thought about how it could look and began working on the door and window mechanism. However, I consider these more related to the physical design than to the hardware itself, since the functionalities and connections are already in place. I’ll keep improving the appearance and details until the PM fair.😊🏠
Week 19 – 25 May
Completed the final version of the smart home system with several significant improvements.

Added a PIR motion sensor to detect movement near the house, with customizable responses. This proved to be challenging at first, as the sensor required proper calibration and debounce logic to avoid false triggers. After some experimentation, I implemented a reliable detection system that works consistently.

Integrated an audio alert system using a passive buzzer with PWM control. Rather than simple on/off functionality, I created distinct audio patterns for different events. The buzzer presented some challenges initially, requiring PWM frequency tuning to produce clear, audible tones.

To solve the persistent LCD display corruption issues that occurred when servos activated, I added 470μF decoupling capacitors across the power rails and implemented a display recovery sequence. This significantly improved system stability by preventing voltage drops from affecting the LCD controller.

Implemented a comprehensive security mode system (Away/Home/Silent) that can be toggled with the keypad's * key. Each mode has different alert behaviors for both the buzzer and LED indicators, allowing users to customize the system based on their needs.

Finalized the physical housing design, adding proper mounting points for all components and creating a functional door and window mechanism.

Hardware

Component	Function
Raspberry Pi Pico W	Main microcontroller with WiFi
KS0203 Humidity Sensor	Measures humidity to detect rain
1602 I2C LCD	Displays environment info & unlock status
Servo Motor #1	Controls automatic door
Servo Motor #2	Controls automatic window
4x4 Keypad Matrix	Secure unlock input
3W LED Module	Basic visual status feedback
Optional: PIR Sensor	Motion detection
Optional: Gas Sensor	Safety detection
Optional: Solar Panel	Battery charging via sunlight

Entire Hardware

LCD Hardware

Outside

Note: Solar power is planned as an optional future extension, not core requirements.

Schematics

Mini Smart Home Schematic

Bill of Materials

Device	Usage	Price (approx.)	Link
2× Raspberry Pi Pico 2 W	Controller with WiFi	39.66 RON each	Optimus Digital
KS0203 Humidity Sensor	Rain detection	20 RON	Keyestudio
LCD 1602 with I2C interface	Display	16.34 RON	Optimus Digital
2× SG90 servomotor	Door and window control	13.99 RON each	Optimus Digital
4x4 Matrix Keypad	Input interface	3.99 RON	Optimus Digital
High power 3W LED module	Visual system indicator	10 RON	FunduinoShop
PIR Motion Sensor (optional)	Motion detection	20 RON	Keyestudio
Mini Solar Panel (optional)	Solar charging (future)	15 RON	Keyestudio
Battery Power Module with Solar Port (optional)	Battery power supply with solar charging	20 RON	Sigmanortec
Breadboard HQ	Circuit prototyping	4.56 RON	Optimus Digital

Note: Not all the links point to Romanian websites. Some parts I already had, so I included links where I could find them easily.

Software

Crate	Version	Purpose	Link
`embassy-rp`	0.3.0	Core functionality for Pico	📦
`embassy-executor`	0.7.0	Async/await execution for embedded	📦
`embassy-time`	0.4.0	Timekeeping and delays	📦
`lcd1602-diver`	0.1.1	LCD 16x2 display driver	📦
`pio`	0.2.1	PIO support for SK6812 LED	📦
`embedded-hal`	0.2.5	Hardware abstraction layer	📦
`defmt`	0.3	Debugging framework	📦
`heapless`	0.8	Stack-based collections	📦
`embassy-sync`	0.6.2	Synchronization primitives	📦
`embassy-futures`	0.1.0	Future utilities for no_std	📦

Description​

Motivation​

Architecture​

Log​

Hardware​

Schematics​

Bill of Materials​

Software​

Links​