The present invention is directed to multi-layer golf balls having a center, a cover layer, and at least one intermediate layer between the core and the cover layer. The LED light source comprises an LED lamp and an LED substrate. When a connectivity failure is detected in the first interconnect type, the network error manager receives from the master subnet manager at least one event notification via a second interconnect type. Thus, using the visible light with specific wavelength as illumination light at night can not only assist users in reading, but also avoid from exciting users’ sympathetic and causing melatonin suppression.