a self - contained stand - alone weighing system comprises at least one weight supporting surface for bearing the weight of an object , at least one transducer coupled to the weight supporting surface for producing a signal indicative of the weight , and a processor for receiving the signal and producing a resultant weight signal . the resultant weight signal is then represented in a form perceptible to humans by a weight indicator . the self - contained weighing system also comprises a rechargeable battery for supplying electrical energy , and a housing for enclosing the weighing system to form a single unit .