User interface (UI) design is the process designers use to build interfaces in software or computerized devices, focusing on looks or style. Designers aim to create interfaces which users find easy to use and pleasurable. UI design refers to graphical user interfaces and other forms—e.g., voice-controlled interfaces. The partition between software running on the CPU and interface hardware is the basic decision in interface design. We can expand on our requirements to identify several factors that influence the decision.
Algorithmic complexity.Some algorithms may be hard to implement as analog or digital circuits due to their size or the nature of the operations they perform.
Flexibility.Flexibility comes in several forms. A software routine may be changed after installation of the system. The software may also provide parameters that adjust its operation without changing the code itself. Updates are definitely easier for software than for hardware interfaces. The more parameters for a given function, the more expensive and difficult is the application of those parameters to a hardware implementation.
CPU utilization.An interface can be used to offload some processing from the CPU. High data rates are particularly taxing for software. The cost of a faster CPU must be balanced against the cost of a more sophisticated hardware interface.
Sample rate.CPUs have some basic limits on the rate at which they can process data. Interrupt handling, RTOS overhead, and software performance all limit the speed with which the CPU can perform a computation. An interface can be used to recognize events or to down sample the signals.
Numerical precision and dynamic range.The range between minimum and maximum values on a signal determines both the number of bits required to represent the signal as well as whether that representation is fixed point or floating point. While floating-point units can be built in hardware, such designs are relatively complex. Number representations with larger bit widths increase the size of hardware data paths. In contrast, software number representations may take up more memory but CPU mechanisms exist for several different number representations of varying accuracy.
Latency.Some algorithms may be hard to implement as analog or digital circuits due to their size or the nature of the operations they perform.
Algorithmic complexity.Software processing adds latency for interrupt processing and RTOS mechanisms; individual operations may require multiple instructions. Digital interfaces may provide low latency and analog interfaces can be highly responsive. Good user interface design facilitates finishing the task at hand without drawing unnecessary attention to it. Graphic design and typography are utilized to support its usability, influencing how the user performs certain interactions and improving the aesthetic appeal of the design; design aesthetics may enhance or detract from the ability of users to use the functions of the interface. The design process must balance technical functionality and visual elements (e.g., mental model) to create a system that is not only operational but also usable and adaptable to changing user needs. Interface design is involved in a wide range of projects, from computer systems, to cars, to commercial planes; all of these projects involve much of the same basic human interactions yet also require some unique skills and knowledge. As a result, designers tend to specialize in certain types of projects and have skills centred on their expertise, whether it is a software design, user research, web design, or industrial design.