pifilter

PiFilter is a modular digital signal processing library designed for embedded systems, with a focus on the Raspberry Pi platform. It provides a framework for building and deploying real-time digital filters through a pipeline of processing blocks. The library emphasizes portability, low latency, and ease of integration with other software components.

The core is implemented in C for performance and is complemented by bindings for higher-level languages such as Python and Lua. The architecture centers on a graph-based processing model in which data samples flow through a chain of filter blocks, each applying a mathematical operation. The system supports multi-channel streams, configurable buffer sizes, and real-time scheduling considerations. Optional SIMD acceleration (for example, NEON on ARM CPUs) can improve throughput on compatible devices.

PiFilter offers a range of filter types, including finite impulse response (FIR) and infinite impulse response (IIR) filters, with common configurations such as low-pass, high-pass, band-pass, and notch filters. Coefficients are configurable at runtime, enabling adaptive or static filtering. Additional features include block-based processing, sample-rate awareness, and basic utilities for testing and visualization in development environments.

The project is released under an open-source license and is distributed via a public repository with documentation and example applications. Typical use cases include audio processing, sensor data conditioning, and educational demonstrations of digital filtering concepts on Raspberry Pi hardware.

See also: digital signal processing, Raspberry Pi, audio processing, FIR, IIR.