DSP Crossover Project

Overview

This project is a Digital Signal Processing (DSP) crossover system designed to manage audio signal using a ESP32 microcontroller and a ADAU1401. The system allows users to adjust crossover filter settings, such as cutoff frequencies, and navigate through a menu to select the L/R crossovers in a LCD display using a rotary encoder and a back button. The ADAU14/1701 has 2 audio inputs and 4 outputs. This setup allows it to set cutoff frequencies for each output, enabling customized audio filtering and signal routing.

Schematics

The project schematic is placed in the docs folder.

Key Components

1. DSP Processing (features/crossover/)

• service.py: Contains the CrossoverService class, which handles the calculation and setting of crossover filter coefficients. It includes methods for setting bandpass cutoff frequencies, calculating filter coefficients, and reading/writing coefficients to the DSP.
• controller.py: Implements the TwoWayCrossover class, which manages the user interface for adjusting crossover settings. It handles cursor movement, frequency adjustment, and interaction with the rotary encoder and back button.

2. Rotary Encoder (features/rotary_encoder/)

• rotary_encoder.py: Implements the RotaryEncoder class, which reads the state of the rotary encoder and emits events (left, right, click) based on user input. These events are sent to the EventBus for further processing.

3. LCD Display (external/lcd/i2c_lcd.py)

• i2c_lcd.py: Provides an interface for controlling an I2C-connected LCD display. It supports basic operations like writing text, clearing the display, and controlling the cursor.

4. Event Bus (features/events/)

• event_bus.py: Implements the EventBus class, which acts as a central hub for event handling. Components can subscribe to events (e.g., click, right, left, back) and respond accordingly.

5. Back Button (features/back_button/)

• back_button.py: Implements the BackButton class, which handles the back button input. It emits a back event when the button is pressed, allowing the system to navigate back to previous menus or cancel actions.

6. Navigator (features/navigator/)

• controller.py: Implements the Navigator class, which manages the current page or state of the system. It interacts with the LCD display and handles navigation events from the rotary encoder and back button.

7. Main Application (main.py)

• main.py: The entry point of the application. It initializes the EventBus, Navigator, RotaryEncoder, and BackButton. It also sets up event listeners and runs the main loop to continuously check for encoder input.

Usage

1. Setup: Ensure that the hardware components (ESP32, rotary encoder, back button, LCD display, and DSP) are properly connected to the microcontroller.
2. Run the Application: Place the repository in the controller. The LCD will display the current state of the system, and the rotary encoder can be used to navigate and adjust settings.
3. Adjust Crossover Settings: Use the rotary encoder to select a filter and adjust its cutoff frequency. Press the encoder button to confirm the selection or the back button to cancel.

Dependencies

• MicroPython: The project is designed to run on MicroPython-compatible hardware.
• I2C LCD Library: The i2c_lcd.py library is used to control the LCD display. https://github.com/dhylands/python_lcd/blob/master/lcd/i2c_lcd.py
• Sigma DSP Library: The sigma_dsp library was adapted to provide the necessary functionality to interact with the DSP. Reference: https://github.com/Wei1234c/SigmaDSP

Contributing

Contributions are welcome! Please open an issue or submit a pull request for any improvements or bug fixes.