a portable safety , entertainment and communication device for a bicycle is provided . the device brings together a plurality of functions in a single device that can be fixed to the handlebar of a bicycle . the device is configured to automatically detect whether a casing is connected to a support and change the functionality of various elements of the device if so . in one aspect , the device changes the functionality of a digital music player so that a user may listen to music through speakers when the casing is connected to the support and listen to music through headphones connected to an audio output port when the casing is not connected to the support . various other modules providing functionality may also be included in the device , such as a video camera and / or digital camera and a light source .