C. U Shape Infrared Sensor
It is a special type of sensor which is U shape. One end of
the sensor has an infrared transmitter while the other has an
infrared receiver, whenever signal is transmitted between the
two end of the U shape infra- red sensor, no voltages are
received between the terminal of the sensor, but if the
transmission is broken a high pulse of 5V is received. This
research involved a conventional meter and a U Shape sensor
in such a manner, so that the aluminum disk of the meter is
fixing between the two terminals of the sensor. A cut on the
aluminum disc is created; whenever disk rotates, the cut comes
in front of the sensor end which makes the path of transmitter
and receiver. When this path is made, a high to low pulse is
generate, which is count by the controller. After 10 pulses there
will be one unit.