Demo Light

A light firmware for the ESP32-C3 board that controls a light bulb connected to a 5 V relay. The light can be switched on or off via HTTP server routes, a physical switch, or automatically based on input from a AM312 PIR motion sensor and a BH1750 ambient light sensor. The board also includes a DS18B20 temperature sensor, whose readings are displayed on an SSD1306 OLED display.

1. demo-light: the main firmware for the ESP32-C3 board, which expects the real sensors and relay to be connected.
2. mock: a testing binary that simulates sensor input, for development and testing without hardware. This firmware uses the built-in LED and the button on GPIO 9 to simulate the light and switch.

It implements an HTTP server that manages the state of the light via REST requests:

• light/on route turns the light on
• light/off route turns the light off
• light/toggle route toggles the light
• light/manual route enables manual mode, allowing control via the physical switch or the /on, /off and /toggle routes
• light/motion-detection route enables motion-based mode, where the light turns on/off based on the AM312 PIR motion sensor
• light/ambient-light route enables ambient-light mode, where the light turns on/off depending on the light level measured by the BH1750 sensor

Each time the light state changes, a JSON message describing the current status is published to the /light/<esp32c3_mac_address>/events topic on an MQTT broker.

The board can be discovered by another node on the same network via an mDNS-SD service.

Wiring

The diagram below illustrates how the components are connected in this demo.

This diagram was created using Fritzing, an open-source tool. The corresponding project file is demo.fzz.

Build

To build the demo-light firmware run:

cargo build --release --bin demo-light

To build the mock firmware run:

cargo build --release --bin mock

To build both of them run:

cargo build --release

Run

To flash and run the demo-light firmware on an ESP32-C3 board:

cargo run --release --bin demo-light

To flash and run the mock firmware on an ESP32-C3 board:

cargo run --release --bin mock

Important

Always use the release profile [--release] when building esp-hal crate. The dev profile can potentially be one or more orders of magnitude slower than release profile, and may cause issues with timing-senstive peripherals and/or devices.

Board usage on WSL

Support for connecting USB devices is not natively available on Windows Subsystem for Linux (WSL).

In order to use the ESP32-C3 board with WSL, follow this guide and manually connect the USB port used by the board to WSL.

Usage Prerequisites

• Rename cfg.toml.example to cfg.toml and populate it with your Wi-Fi credentials: ssid, password, broker_address, broker_port
• Connect the board to a laptop via a USB-C cable to view the logs
• Pin the project to a specific nightly version for more stability, if needed