Abstract: A power adapter may include a power output module configured to supply electric current to a computing device, an electrical monitor configured to measure an output electrical quantity of the power output module, a communication port configured to receive, from the computing device, an indication of an input electrical quantity, a comparator configured to determine a difference between the measured output electrical quantity and the indicated input electrical quantity, and a controller configured to instruct the power output module to stop supplying the electric current to the computing device based on the difference satisfying a warning state.

Abstract: Certain aspects relate to a cordless powered light marking apparatus that can be used with a pointing device and information processor to enable a program to be executed by the information processor. In certain embodiments, the cordless light marking apparatuses are “solar-powered.” In some cases, the cordless light marking apparatus may be self-powered in a different manner, such as via rechargeable batteries (e.g., lithium ion), alkaline batteries, etc. Other aspects relate to applications of the cordless light marking apparatuses. For example, multiple display devices connected directly or indirectly to one information processor may each have a light marking apparatus, enabling multiple players to interact substantially simultaneously with the same information processor through different display devices and different pointing devices. Further, the information processor may be accessed at different times through different display devices, without needing to move the processor or light marking apparatus.