Monday, August 12, 2013
Drinking Water Alarm
Drinking Water Alarm
State Jal Boards supply water for limited duration in a day. Time of
water supply is decided by the management and the public does not know
the same. In such a situation, this water alarm circuit will save the
people from long wait as it will inform them as soon as the water supply
starts. At the heart of this circuit is a small water sensor. For
fabricating this water sensor, you need two foils—an aluminium foil and a
plastic foil. You can assemble the sensor by rolling aluminium and
plastic foils in the shape of a concentric cylinder. Connect one end of
the insulated flexible wire on the aluminium foil and the other end to
resistor R2. Now mount this sensor inside the water tap such that water
can flow through it uninterrupted. To complete the circuit, connect
another wire from the junction of pins 2 and 6 of IC1 to the water
pipeline or the water tap itself. The working of the circuit is simple.
Timer
555 is wired as an astable multivibrator. The multivibrator will work
only when water flows through the water tap and completes the circuit
connection. It oscillates at about 1 kHz. The output of the timer at pin
3 is connected to loudspeaker LS1 via capacitor C3. As soon as water
starts flowing through the tap, the speaker starts sounding, which
indicates resumption of water supply. It remains ‘on’ until you switch
off the circuit with switch S1 or remove the sensor from the tap. The
circuit works off a 9V battery supply. Assemble the circuit on any
general-purpose PCB and house in a suitable cabinet. The water sensor is
inserted into the water tap. Connect the lead coming out from the
junction of 555 pins 2 and 6 to the body of the water tap. Use on/off
switch S1 to power the circuit with the 9V PP3 battery.
