Abstract: A light-emitting user input device can include a touch sensitive portion configured to accept user input (e.g., from a user's thumb) and a light-emitting portion configured to output a light pattern. The light pattern can be used to assist the user in interacting with the user input device. Examples include emulating a multi-degree-of-freedom controller, indicating scrolling or swiping actions, indicating presence of objects nearby the device, indicating receipt of notifications, assisting pairing the user input device with another device, or assisting calibrating the user input device. The light-emitting user input device can be used to provide user input to a wearable device, such as, e.g., a head mounted display device.