A stylus includes a tube body, a touch end connected to the tube body, an inflatable balloon enwrapping the tube body such that the tube body and the balloon cooperatively define a sealed chamber, and an inflating mechanism for inserting gas into the sealed chamber to inflate the balloon and therefore, the size of the stylus is adjustable and convenient for using. A core surrounds an inside and an outside of the bobbin by combining a pair of upper cores with a pair of lower cores. The system also includes at least a first and a second servo. The signal processing system further includes a second signal processing center configured to receive the calculated interference from the first signal processing center. Then, the processor selectably determines the payment option to direct a transmission of funds from at least one payment source to at least one payee account based on an optimization determination performed by the processor.