A simple electronic system for automatic telemetering raingauge

The article describes a simple electronic logic circuit developed in the Instruments Division, Meteorological Office, Pune for automatic telemetering of rainfall data. The sensor is a tipping bucket raingauge which gives a momentary electrical pulse output for every millimetre of rainfall. The cumulative number of such electrical pulses is counted and stored in a four digit BCD electronic counter. A crystal clock turns the system control circuit 'on' once every three hours. Under the control of the circuit programme the station code and the data bits stored in the counter are transferred in parallel to a shift register and then they are shifted out serially. The output is then converted to a short note or a long note corresponding to a logical zero state or one state, shifted out serially from the shift register. Two BCD words are used for station identification. In a single transmission the station code and data is repeated four times and then the control circuit automatically switches off the system.