Spark-Computer Interface

A spark-computer interface, or SCI for short, sometimes erroneously called a brain-computer interface or BCI, is an osteoaugment that allows a fae to operate a computer with their spark. The spark controls the osteoaugment itself, which broadcasts data (usually via infrared) to the device.

Personal computers and portable devices use commercial-grade SCIs that give limited control. More sophisticated (and expensive) SCIs allow for more control; these are often made for more specialized use and require training to use.

The refresh rate for the device's outputs vary from 33⅓ Hz for low-end devices (equal to one quarter of the standard electrical frequency of grid power) to well over 300 Hz for higher-end industrial devices.

Spark to Computer

A typical spark-computer interface supports two channels of communication between the spark and the device, each supporting two bits of data. Each channel measures certain inputs from the spark and outputs the highest, or "most confident", single two-bit value of a certain relative strength or better. SCIs cannot handle multiple inputs in a single channel.

The standard practice among devices is to describe first channel inputs as directions: left (00), right (01), up (10), and down (11); and second channel inputs as the classical elements: heat (00), cold (01), sky (10), and ground (11). The device responds to a rising and usually a continued input. A lack of any sufficiently strong input in a channel is treated as no input.

Some devices can interpret the inputs with strength as well; these are often dubbed analog SCIs. Most often, the strength is an additional two-bit number. These devices are less common, as they are expensive and difficult for most fae to use with good precision.

The first channel is usually used for navigation, such as selecting a menu option or moving a cursor. The second channel varies between devices.

Computer to Spark

Spark-computer interfaces usually do not return output to the spark. Those that do require training in its use, as signals may feel nebulous.