Smart Bin Documentation (#947)

* Smart Bin Documentation

* Documentation Fix

* Changed image format

* Added classroom git repository

* Hardware Documentation Update

* FINAL Hardware Documentation

* Updated photo name

Author: RobertP1021

website/versioned_docs/version-acs_cc/project/2026/robert.postolache/arhitecture_final.webp

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+# Smart Bin
+
+:::info
+
+**Author:** Robert Postolache 
+**GitHub Project Link:** https://github.com/UPB-PMRust-Students/acs-project-2026-RobertP1021
+
+:::
+
+## Description
+
+Smart Bin is a trash bin that automatically sorts waste without any user intervention. When it detects a hand nearby, it opens a flap and lets the object fall onto an internal analysis platform. There, humidity, metal, and weight sensors analyze the object and classify it into one of three categories: wet, dry, or metal. A motor then rotates the container platform until the correct one is in position, after which the object is released. If a container is full, the system refuses to accept new waste for that category.
+
+## Motivation
+
+My motivation to tackle this project came from my daily commute to work. Every day, before getting on the metro, I would buy a coffee cup and something to eat. Sometimes, if the metro was in the station, I hurriedly threw the cup and the food wrapper in the nearest trash bin, without looking for the correct label. So while I was searching for a project idea, I remembered that it would be nice to have a trash bin that could automatically sort the waste, without me having to worry about it.
+
+## Architecture
+
+Smart Bin is built around an STM32U545RE-Q Nucleo board that coordinates all sensors and actuators through firmware written in Rust with Embassy.
+
+**Main flow:**
+
+1. The proximity sensor detects a hand at the entry and the first servo opens the entry flap
+2. The object falls onto the analysis platform where the following are read simultaneously:
+   - humidity sensor
+   - metal sensor
+3. Based on the readings, the microcontroller classifies the object as WET / DRY / METAL
+4. The fill level of the target container is checked (one infrared sensor per container)
+5. If the container is available: the stepper motor rotates the turntable to the correct position, the second servo releases the object
+6. The display shows feedback to the user about the classification result and if a container is full or not
+
+**Interfaces used:**
+- SPI: ST7735 LCD Display
+- PWM: servo × 2
+- GPIO: stepper motor, metal sensor, infrared reflective sensors × 3
+- ADC: humidity sensor
+
+![Architecture Diagram](./arhitecture_final.webp)
+
+## Log
+This will be updated as I continue developing the project
+
+### Week 5 - 11 May
+I bought the hardware components, and mapped out the pin connections. I started testing each component with simple and minimal code. 
+
+### Week 12 - 18 May
+I completed the initial testing for each component, and presented them to the lab assistant.
+
+### Week 19 - 25 May
+TODO
+
+## Hardware
+
+### Schematics
+
+![Hardware Schematic](./pm_proiect_schematic.webp)
+
+### Bill of Materials
+
+| Device | Usage | Price |
+|--------|-------|-------|
+| [STM32U545RE-Q Nucleo](https://www.st.com/en/evaluation-tools/nucleo-u545re-q.html) | Microcontroller | 90 RON |
+| [Servo Motor SG90 × 2](https://www.optimusdigital.ro/en/servomotors/26-sg90-micro-servo-motor.html?search_query=SG90&results=5) | Entry flap + platform trapdoor | 13,99 RON × 2 |
+| [TCRT5000 Reflective Photoelectric Sensor x 3](https://www.optimusdigital.ro/en/optical-sensors/42-tcrt5000-photoelectric-sensor.html?search_query=TCRT5000&results=4) | Container fill level detection | 1.49 RON × 3 |
+*OR*
+| [TCRT5000 Infrared Line Sensor Module with Adjustable Sensitivity x 3](https://www.optimusdigital.ro/en/optical-sensors/2415-modul-senzor-infrarou-de-linie-cu-sensibilitate-reglabila.html?search_query=TCRT5000&results=4) | Container fill level detection | 3.87 RON × 3 |
+| [ULN2003 Stepper Driver + 5V Stepper Motor](https://www.optimusdigital.ro/en/stepper-motors/101-stepper-motor-with-uln2003-driver.html?search_query=stepper&results=97) | Stepper motor control for turntable | 16.97 RON |
+| [HR202L Resistive Humidity Sensor](https://www.optimusdigital.ro/en/humidity-sensors/590-senzor-rezistiv-de-umiditate-hr202l.html?search_query=rain+sensor&results=46) | Humidity sensor for wet/dry | 3.99 RON |
+*OR*
+ [Rain Sensor Module](https://www.optimusdigital.ro/en/humidity-sensors/5775-rain-sensor-module.html?search_query=rain+sensor&results=46) | Humidity sensor for wet/dry | 9.99 RON |
+| [Senzor inductiv de proximitate - LJ12A3-4-Z/BX](https://ardushop.ro/ro/senzori/2182-senzor-inductiv-de-proximitate-lj12a3-4-z-bx-6427854033659.html) | Inductive proximity sensor for metal detection | 15.57 RON |
+| [Senzor Ultrasonic de Distanță HC-SR04+](https://www.optimusdigital.ro/ro/senzori-senzori-ultrasonici/2328-senzor-ultrasonic-de-distana-hc-sr04-compatibil-33-v-i-5-v.html?search_query=HC+SR04&results=15) | Ultrasonic sensor for hand detection | 14.99 RON |
+| [1.8 Inch 128 x 160 SPI TFT LCD Display Module ST7735 51/AVR/STM32/ARM 8/16 Bit ](https://www.amazon.de/-/en/Inch-Display-Module-ST7735-STM32/dp/B0B5RVX9BJ/ref=sr_1_5?crid=3OK9OD7CNSDQD&dib=eyJ2IjoiMSJ9.3_7bMaePwHiqT1VxJiDDYqMcf3MEYLs08db-A_noB2P4Km6v76rcO_IJ4UkdW2pKzx1nqF7hgj7hQwZO4oEUuQME23v1ycsK3XGmjYy8MhmZR3uXl4h4CjTXwQsQCQTv8zN5mkAJJkTlzr5h6mszg0E6Sb5RWU9VKmjLE18jA_CcQnokLxzeciWPpmBwJ2cjKuT4iVTUluNs2XoKtIuE8sIS5NBn381Fxy5ooGhK3CQ.FA72fIsMv7lud416DvWnN5Qno7Ko7FT2j4F5Fz0FYQE&dib_tag=se&keywords=ST7735+LCD+Display&qid=1776722780&sprefix=st7735+lcd+display%2Caps%2C199&sr=8-5) | Display for user feedback | 45.86 RON |
+| Breadboard + Jumper Wires | Connections | 15 RON |
+| Resistors assorted | Pull-ups, current limiting | 5 RON |
+
+## Software
+
+| Library | Description | Usage |
+|---------|-------------|-------|
+| [embassy-stm32](https://github.com/embassy-rs/embassy) | Async HAL for STM32 | Pin control, PWM, SPI, ADC |
+| [embassy-executor](https://github.com/embassy-rs/embassy) | Async executor for embedded | Running concurrent tasks |
+| [embassy-time](https://github.com/embassy-rs/embassy) | Async timers and delays | Timing for sensors and motors |
+| [embassy-embedded-hal](https://github.com/embassy-rs/embassy) | Embedded HAL adapters for Embassy | SPI bus sharing for display |
+| [embedded-graphics](https://github.com/embedded-graphics/embedded-graphics) | 2D graphics library for embedded | Rendering text on the display |
+| [embedded-hal](https://github.com/rust-embedded/embedded-hal) | Hardware abstraction layer traits | PWM control for servo motors |
+| [mipidsi](https://github.com/almindor/mipidsi) | Display driver for MIPI displays | ST7735 display driver |
+| [display-interface-spi](https://github.com/therealprof/display-interface) | SPI display interface | SPI communication with ST7735 |
+
+
+## Links
+
+1. [Embassy - Async framework for embedded Rust](https://embassy.dev/)
+2. [STM32U545RE-Q Nucleo Documentation](https://www.st.com/en/evaluation-tools/nucleo-u545re-q.html)
+3. [embedded-graphics](https://github.com/embedded-graphics/embedded-graphics)
+4. [PM Course Website](https://embedded-rust-101.wyliodrin.com/)