Simple pipe leakage warning device
Water, if there are no leaks, is a blessing. But if she flooded the apartment, then it becomes a problem that ends in moral, financial troubles. They fight it with regular inspections of water supply and heating networks, identifying places of defects, rust, eliminating them. Leaving the house, block the input cranes, valves.
There is a way to improve control by providing leakage protection in the house. It provides for the presence of flooding in problem areas. Devices are different, but working on the same principle: there is an element that responds to the presence of liquid and gives a signal to turn on the executive module. As a result, a light or sound signal is supplied, the valve may overlap.
More often in practice, craftsmen make contact sensors for water leakage. They used the property of a fluid to conduct an electric current. There are several schemes for such devices. You can do it by focusing on the simplest one, running on a battery of 9 V. The cost of radio components in it is cheap, you can purchase them in any specialized store. Making a device is not difficult.
In the simplest flood detector circuit, there is a battery, an audible alarm, a transistor and a resistor. The first three elements are included in a closed circuit: from the "plus" of the battery to the "plus" of the buzzer; further, the minus of the audible warning device is connected to the collector of the transistor; the emitter of the transistor is connected to the "minus" of the battery. From the third output of the transistor - the base - a jumper is arranged through the resistor to the portion of the circuit between the battery and the "plus" of the buzzer. In the area from the resistor to the circuit, a gap with electrodes is built.
The transistor in the circuit is a basic element with an npn junction. Suitable, included in the BC series with numbers 515 (preferred), 518, 517. He is in the circuit responsible for supplying voltage to the audible warning device.
The latter may be the simplest buzzer in which the generator is built. It costs from a penny. The resistor in the circuit is 10K.
In the absence of water, the transistor is locked and does not pass current to the buzzer. When the fluid connects the electrodes in the gap, voltage will be applied to the base of the transistor. The latter leads to the opening of the emitter of the transistor and the power supply to the buzzer, which begins to squeak. In parallel with the buzzer, you can place an LED in the circuit, which will add reliability to the signaling device.
Electrodes are made of metal, which does not corrode upon contact with water. It can be, for example, a copper conductor - its ends are stripped, tinned.
To assemble the described circuit, a breadboard is used. Then everything is placed in a plastic box, for example, a soap box. To contact with water in the bottom make a couple of holes.