Disclosed herein are finger-worn devices in various embodiments, and related systems, interfaces and methods of use. In some embodiments, a finger-worn device may be connected and disconnected from other devices. In some embodiments, a finger-worn device may relay tactile information to a finger wearing said finger-worn device, and/or to a finger operating said finger-worn device. In some embodiments, a finger-worn device may be operated to generate sound, whereas in some embodiments, a finger-worn device may be operated to generate visual output. In some embodiments, interfaces are intended to react, or be controlled or influenced by a finger-worn device or plurality thereof. In some methods, a finger-worn device may be operated for registering input in systems which can sense and process sounds, whereas in other methods a finger-worn device may be operated for registering input in systems which can sense and process light.