Rust-Powered Smart Trash Bin (Garbage Collector, kind of)

Overview

This project was prepared for the Rust Warsaw Meetup. It is a fun and practical IoT device: a smart trash bin that detects when it’s full and buzzes to let you know it’s time to take out the trash.
It’s powered by an ESP32-C3 microcontroller and written entirely in Rust.

• Detects weight using a load cell and HX711 amplifier
• Buzzes when the bin is full (weight threshold exceeded)
• Logs weight readings to the serial console
• Beginner-friendly Rust code and hardware setup

Presentation slides: presentation.pdf

Hardware Used

• ESP32-C3 development board
• Load cell (weight sensor)
• HX711 load cell amplifier/ADC module
• Active buzzer (5V, controlled via NPN transistor, e.g. BC550C)
• NPN transistor (e.g. BC550C) + 1kΩ resistor (for buzzer switching)
• Breadboard and jumper wires

Wiring Diagram

Component	ESP32-C3 Pin	Notes
HX711 DT	GPIO2	Data pin
HX711 SCK	GPIO3	Clock pin
Buzzer (+)	5V
Buzzer (–)	Collector of NPN transistor
Transistor base	GPIO5 via 1kΩ resistor
Transistor emitter	GND

How It Works

1. The load cell senses the weight of the trash bin.
2. The HX711 module amplifies and digitizes the signal.
3. The ESP32-C3 reads the weight value.
4. If the weight is above a set threshold, the buzzer turns on.
5. Otherwise, the buzzer stays off.
6. Weight readings are logged every second for debugging.

Getting Started

Prerequisites

• Rust toolchain
• espup for ESP32 Rust setup
• esp-idf-sys and esp-idf-hal crates
• cargo-generate for project templates

Quick Start

1. Set up Rust for ESP32:

   cargo install espup
   espup install
   source ~/export-esp.sh

2. Generate a new project:

   cargo generate --git https://github.com/esp-rs/esp-idf-template cargo

3. Clone this repo and build:

   git clone https://github.com/Artur-Sulej/esp_load_cell
   cd esp_load_cell
   cargo build

4. Flash to your ESP32-C3:

   cargo run
   # or use espflash if needed

Why Rust and ESP32?

• Rust is safe, modern, and fun for embedded projects.
• ESP32-C3 is a powerful, WiFi-enabled microcontroller for just a few dollars.
• The esp-idf ecosystem brings robust drivers and FreeRTOS support to Rust.

Credits

• Inspired by the Rust Warsaw Meetup community
• Thanks to @Gosia Haruba and vlayer labs for organizing the event!

License

MIT