My Circuit

Aburst water-supply hose of the washing machine, a bathroom tap that you forgot to close, or a broken aquarium wall may turn your house into a pond. You can avoid this mess by using an electronic water alarm that warns you of the water leakage as soon as possible. The acoustic water alarm circuit presented here takes advantage of the fact that the tap water is always slightly contaminated (or has salts and minerals) and thus conducts electricity to a certain extent. It is built around IC LMC555 (IC1), which is a CMOS version of the bipolar 555 timer chip. IC1 is followed by a complementary pair of emitter followers (T1 and T2) to drive a standard 8-ohm speaker (LS1). Power is supplied by a compact 9V PP3 battery.  Simple Electronic Water Alarm Circuit Diagram :   Power is applied when power switch S1 is closed. The reset input (pin 4) of IC1 is held low by resistor R1 (2.2-kilo-ohm). The astable oscillator wired around IC1 is in disabled mode. When probes P1 and P2 become wet, these co...

Simple, two-wire, remote monitoring unit, Three-LED level display, 9V battery powered. The whole project was developed on a friend's request. Its purpose was to remotely monitor the water-level in a metal tank located in the attic by means of a very simple control unit placed in the kitchen, some floors below. Mains requirements were: No separate supply for the remote circuit Main and remote units connected by a thin two-wire cable Simple LED display for the main unit Battery operation to avoid problems related to mains supply and water proximity As the circuit was battery operated a low current consumption was obviously welcomed The very small remote unit is placed near the tank and measures the water level in three ranges by means of two steel rods. Each range will cover one third of the tank capacity: Almost empty - signaled by means of a red LED (D3) in the control unit display About half-level - signaled by means of a yellow LED (D2) in the control unit display Almost full -...

Most of the circuits for multi-level indication/control of water in tanks employ a bunch of wires running between the circuit and the overhead tank, which accounts for almost half the cost of the entire project. Here is an intelligent scanned water-level indicator-cum-pump controller circuit (Fig. 1) that utilises just four wires to the overhead tank to indicate nine different levels. The connection arrangement for the overhead tank (OHT) and the underground tank (UGT) is shown in Fig. 2. Two wires from the circuit in Fig. 1 run to the underground/ground-level tank (to output line K and return line J, respectively) to check the availability of water in the tank before operating the pump, thereby guarding the pump against the damage due to dry running. Fig. 1: Intelligent water-level indicator-cum-water pump controller The scanning section employs an NE555 timer (IC1) wired as an astable multivibrator to oscillate at around 1 kHz. The output of NE555 is connected to CLK inputs of two CD...

This circuit not only indicates the amount of water present in the overhead tank but also gives an alarm when the tank is full. The circuit uses the widely available CD4066, bilateral switch CMOS IC to indicate the water level through LEDs. When the water is empty the wires in the tank are open circuited and the 180K resistors pulls the switch low hence opening the switch and LEDs are OFF. As the water starts filling up, first the wire in the tank connected to S1 and the + supply are shorted by water. This closes the switch S1 and turns the LED1 ON. As the water continues to fill the tank, the LEDs2 , 3 and 4 light up gradually. The no. of levels of indication can be increased to 8 if 2 CD4066 ICs are used in a similar fashion. When the water is full, the base of the transistor BC148 is pulled high by the water and this saturates the transistor, turning the buzzer ON. The SPST switch has to be opened to turn the buzzer OFF. Remember to turn the switch ON while pumping water ...

This circuit has been very useful in filling a header tank for a reticulated water supply on a farm. Eight troughs are supplied in different paddocks where a lack of water would have serious consequences for the stock. In the past, the tank had been filled daily by a time clock which was not successful. During hot weather, the stock would empty the tank on a regular basis and then be without water for several hours or the tank would overflow and flood the area if the weather was wet and the cattle did not drink much.1  Circuit Diagram: Automatic Water Tank Filler Schematic Circuit Diagram The circuit described has been used to maintain the level of water in the header tank within prescribed limits. It controls a 3HP submersible bore pump which has a high starting current, necessitating a solid-state relay sufficient to take the starting load. Two Darlington transistors, Q1 & Q3, in conjunction with Q2 & Q4, are connected to the upper and lower water sensors in the tank. Q2 ...

The water-tank level meter de-scribed here is very simple and useful for monitoring the water level in an overhead tank (OHT). The water level at 30cm intervals is monitored and continuously indicated by LEDs ar-ranged in a meter-format. When all the LEDs are ‘off’, it indicates that the OHT is empty. When the water level reaches the top limit, the whole LED-meter begins to flash. The height at which the level-sensing electrodes are fitted is adjustable. Thus, the minimum and maximum level settings may be varied as desired. The range of the meter can also be enlarged to cater to any level. No special or critical components are used. CMOS ICs are used to limit the idle current to a minimum level.   Even when all the LEDs are ‘on’, i.e. water reaches the top level, the demand on the power supply is reasonably low. Further, the extremely high input resistance of the Schmitt inverter gates reduces the input current and thus minimises the erosion of electrodes. The princi-pal part of the de...