Evolution and Local Interaction with One Forward-Looking Player

An electric vacuum cleaner which has a plurality of indicating lamps L1-L6 for being lighted in steps to indicate the power levels of the motor which has simple construction at connecting parts of the pipes, and which, comprises a plurality of indicating lamps which are provided on the nozzle part to indicate the power levels of the motor in steps; a power-source providing leads which extends from the body to the nozzle part; a control circuit which controls the power of the motor; a light-emitting element which emits optical signals based on the power signal generated by the control circuit; an optical-signal passage which is provided through the extension pipe in order that the optical-signals travel straight; a light-detecting element which receives the optical signals travelled from the light-emitting element; and driving circuitry for driving a plurality of the indicating lamps based on the signals received at the light-detecting element, is constructed in such a way that the power levels of the motor are converted into the optical signal at the light-emitting element (30) and then transmitted to the light-detecting element (40) through the light-signal passage (50), therefore electric pins for transmitting the output signals, which were conventionally required at the connecting part of the pipes, are now completely unnecessary.