lm_sensors provides essential tools for monitoring the temperatures, voltages, and fans of Linux systems with hardware monitoring devices. It contains a library for sensors access (libsensors), a command-line tool for sensor reporting (sensors), and a daemon (sensord). It also contains scripts for sensor hardware identification and fan speed control.
The Advanced Linux Sound Architecture is composed of several parts. The first is a fully modularized sound driver which supports module autoloading, devfs, isapnp autoconfiguration, and gives complete access to analog audio, digital audio, control, mixer, synthesizer, DSP, MIDI, and timer components of audio hardware. It also includes a fully-featured kernel-level sequencer, a full compatibility layer for OSS/Free applications, an object-oriented C library which covers and enhances the ALSA kernel driver functionality for applications (client/server, plugins, PCM sharing/multiplexing, PCM metering, etc.), an interactive configuration program for the driver, and some simple utilities for basic management.
DirectFB is a thin library that provides developers with hardware graphics acceleration, input device handling and abstraction, an integrated windowing system with support for translucent windows and multiple display layers on top of the Linux framebuffer device. It is a complete hardware abstraction layer with software fallbacks for every graphics operation that is not supported by the underlying hardware.
v4l-utils is a collection of various video4linux (V4L) and DVB utilities. libv4l is an accompanying collection of libraries that adds a thin abstraction layer on top of video4linux2 (V4L2) devices. The purpose of this layer is to make it easy for application writers to support a wide variety of devices without having to write separate code for different devices in the same class. It consists of 3 different libraries. libv4lconvert offers functions to convert from any (known) pixel format to V4l2_PIX_FMT_BGR24 or V4l2_PIX_FMT_YUV420. libv4l1 offers the (deprecated) v4l1 API on top of v4l2 devices, independent of the drivers for those devices supporting v4l1 compatibility (which many v4l2 drivers do not). libv4l2 offers the v4l2 API on top of v4l2 devices, while adding support for the application transparent libv4lconvert conversion where necessary.
ServoMaster provides hardware independent abstractions to servos and servo controllers. It has implementations for several servo controller families, including Phidget, Pololu, Parallax, and SSC. It has support for servo and controller metadata, introspection, and capabilities discovery.
Dmx4linux is a driver package for accessing DMX interfaces with Linux. DMX is a protocol for controlling devices supporting DMX512 like dimmers, moving lights, or scanners. Many commercial and free interfaces are supported. The package includes some simple console and X applications to test the drivers and your hardware immediately.
parapin makes it easy to write C code under Linux that controls individual pins on a PC parallel port. This kind of control is very useful for electronics projects that use the PC's parallel port as a generic digital I/O interface. Parapin goes to great lengths to insulate the programmer from the somewhat complex parallel port programming interface provided by the PC hardware, and comes as a user-space C library, or linked as part of a Linux kernel module.