| 摘要 |
A shower head volume meter producing an audible or other alarm for indicating when a predetermined volume of water has been delivered. A polite alarm or "beep" is used after a first volume of water y has been delivered, while an aggressive alarm in the form of a continuous sound is used after a second volume of water y+z has been delivered. A first embodiment measures the volume of water with a magnetic turbine and pick-up coil. The turbine rotates in response to water flow through meter generating a rotating magnetic flux. The flux lines cut across the pick-up coil which produces electrical pulse signals at a rate corresponding to the water flow rate. The number of magnetic poles in the turbine determines the total volume of water that can be delivered. A microcontroller analyzes the pulse signals and initiates the alarm. The pick-up coil doubles as an alternator to produce electrical power for the microcontroller. A second embodiment measures the volume of water using the pressure difference caused by the venturi effect. A piezoresistive die produces a voltage corresponding to the water flow rate. The meter can be a separate screw or adapter or an integral part of the shower head.
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