Do-it-yourself homemade water leak sensor (flood sensor)

Water is life. If it is in the tap, or in the heating radiator, this is good. And if it is on the floor of your apartment, or on the ceiling of your neighbor below, this is a big financial and moral problem. Of course, it is necessary to regularly check the water supply and heating system for corrosion or cracks in plastic pipes. However, a water breakthrough usually occurs suddenly, without any sign of impending danger. It’s good if at this moment you are at home and not sleeping. But, according to the law of meanness, leaks occur at night, or when you are not at home.

Simple rules for dealing with this problem (especially for old housing stock, with worn-out networks):

• Regularly inspect water pipes and heating system elements for defects, spot rust, tight connections, etc.
• When leaving home, close the entrance valve on the riser.
• Outside the heating season, close the taps on the radiators (if any).
• Use a leakage protection system.

We will consider the last item on the list in more detail.

How to signal a water leak

The solution to the problem came into everyday life from the yachting world. Since the ship's lower tier rooms (especially holds) are located below the waterline, water regularly accumulates in them. The consequences are clear, the question is how to deal with it. It is irrational to assign a separate sailor on watch for control. Then who will give the command to turn on the sump pump?

There are effective tandems: a water presence sensor and an automatic pump. As soon as the sensor detects that the hold is full, the pump motor turns on and pumping occurs.

The water sensor is nothing more than a regular float on a hinge connected to the pump switch. When the water level rises by 1–2 cm, the alarm and the sump pump motor are triggered at the same time.

Comfortable? Yes. Safely? Of course. However, such a system is unlikely to be suitable for a residential building.

• Firstly, if the water reaches a level of 1–2 cm over the entire area of ​​the room, it will run through the threshold of the front door onto the landing (not to mention the neighbors below).
• Secondly, a bilge pump is completely unnecessary, since the cause of the breakthrough must be immediately found and localized.
• Thirdly, the float system for rooms with a flat floor is ineffective (unlike watercraft with a keeled bottom). By the time the “required” level for operation is reached, the house will fall apart from dampness.

Therefore, a more sensitive alarm system against leaks is needed. This is a question of sensors, and the executive part comes in two types:

1. Alarm only. It can be light, sound, or even connected to a GSM network. In this case, you will receive a signal on your mobile phone and will be able to remotely call an emergency team.

2. Turning off the water supply (unfortunately, this design does not work with the heating system, only water supply). After the main valve, which supplies water from the riser to the apartment (it does not matter whether it is before or after the meter), an electromagnetic valve is installed. When a signal is sent from the sensor, the water is shut off and further flooding is stopped.

Naturally, the water shut-off system also signals a problem in any of the above ways. These devices are offered in a wide range by plumbing stores. It would seem that material damage from a flood is potentially higher than the price of peace of mind. However, the majority of citizens live by the principle “until thunder strikes, a man will not cross himself.” And more progressive (and prudent) homeowners make a water leakage sensor with their own hands.

Standard configuration

Any leakage protection system, as already noted, has the same elemental base, which consists of:

• ball(s) electric crane(s);
• controller;
• sensor(s).

Ball Valves

An electric faucet for anti-leakage systems has several parameters, of which the most important are the closing speed, dimensions and material of manufacture.

The time it takes for the electric crane to close has the most significant effect on the overall response time of the protection. The speed of closure directly determines how much water will have time to leak before the causes of the emergency are eliminated.

The dimensions of the electric faucet determine its capabilities in terms of implementation in a particular plumbing installation. Usually indicated in the characteristics of the set (on the box, in the product description on the online store page).

The material of the electric crane frame greatly affects its durability. The most reliable and safe taps are those made of stainless steel and brass with nickel plating.

Controller

The controller must be autonomous so that the system does not depend on periodic (or emergency) power outages. In modern leakage protection devices, sometimes even 2 backup power supplies are installed, which continue to supply the controller with electricity after the main one (220 volt network) is turned off and the autonomous (battery) power supply is discharged. In Aquawatch sets, the 3rd power element is connected via a USB interface.

Controllers that support wireless sensors are doubly valuable, as they can be used where laying wires is simply not possible.

The response to the bay should be minimal. The controller is not required to mechanically interact with the water pressure, unlike an electric faucet, so the response time of the system should be reduced to the maximum possible to the closing speed of the latter.

Sensors

Any good flood protection system is not least assessed by the maximum number of connected sensors. Very often, a sufficient condition for ensuring reliable protection against pipe leaks is the installation of 4 sensors. But this applies to apartments and houses. The use of a system in a production environment, for example, is fraught with the need for a much larger number of them, which is duly taken into account by its designers.

Taking into account the operational characteristics, namely the length of the sensor wire, the ease of replacing failed sensors, the presence of an anti-oxidation coating on their contacts, will help in the future to avoid many difficulties during installation and actual leakage monitoring.

Classification of sensors by nature of operation

Devices are distinguished in different ways, one of them is the capabilities and behavior of the gadget in a critical situation.

1. The device body contains all the functionality that ensures its autonomous operation. A leak alert is indicated by a sound or light signal. There are models that signal the presence of deviations in the operation of the water supply system in the form of an SMS message to the phone.
2. Information about leakage through the wired system is sent to the control panel. This electronic device, after receiving an alert, processes the data and gives a command to the solenoid valve, which can turn off the water supply. This is the principle used by the AquaStorh water leak protection system.
3. The wireless leak protection system differs from the previous one in that the sensors send signals to the remote control using radio communication.

The principle of operation of the anti-leakage system

It is clear that if an accident occurred on the central water supply riser in an apartment, no “hitchhiking” system will help. Just shut off the water supply to the entire entrance or house.

But there are many reasons for concern in your apartment:

1. The indoor pipes themselves, joints, and faucets wear out over time and become the cause of accidents.
2. Household appliances themselves - washing machines and dishwashers - have their own period of trouble-free operation. Over time, rubber seals and water supply tubes lose their strength and elasticity. If they are not replaced in time, then the next repair will be on the neighbors below. And most likely at your expense.
3. Independent installation of pipelines and connection of plumbing equipment - toilet, bathtub, shower, washing machines and dishwashers - is also a common cause of apartment floods.
4. Let's not forget about the human factor. Elementary forgetfulness leads to overflowing of the bathtub and, as a consequence, to flooding of the lower floors.

The standard anti-leak system reacts to any contact with water on the floor. The water sensor can be placed anywhere - a bathroom, kitchen, under a bathtub, or where there is a possible water pipe break.

How does such a system work?

All water leakage detectors are based on the presence of a pair of electrodes.

Upon contact with water, the electrical circuit closes. The signal about a decrease in resistance goes directly to the controller, which processes the received information and sends its electrical signal to activate the solenoid valves installed on the water supply pipes to the apartment.

Water will not flow into the house until the causes of the accident are eliminated. And only after this the system will be started again and the water supply taps will open.

Such complexes operate autonomously and automatically.

What to consider in a flood sensor

It is worth knowing the important aspects when choosing a water leakage sensor. When choosing a protective device, it is necessary to take into account its characteristics:

1. Method and place of attachment. The system should be located where there will be no erroneous signals about the occurrence of an emergency if water accidentally gets on the sensors or if there is a high humidity level in the room.
2. Power supply. Are there any requirements for the installation of the system when using industrial voltage? It is better to buy devices that run on batteries.
3. Sensitivity threshold. You can adjust the sensors for sensitivity or not.
4. Manufacturer. When a device is purchased in a store, it comes with a warranty. In case of breakdown, technical assistance is provided.
5. Time to close the tap. The lower it is, the less chance of flooding.
6. Availability of battery. If wired equipment is installed, provision should be made for the system to operate autonomously when the power supply is turned off.
7. Model type. A wireless system costs more.

Water sensors are widely used in household appliances. If connected correctly, the device will last much longer than a homemade circuit. Water flood regulators are in demand among the population, because the low quality of pipe connections and cheap Chinese taps leads to more frequent accidents recently. When the device hits a sensitive water sensor, it raises an alarm in time.

Composition and diagram of a standard protection device

Standard equipment includes:

1. Ball valves with an electric drive, with the help of which the function of blocking the flow of water in pipes is realized. The valve interrupts the flow and reports an accident. One of the disadvantages of the wedge method of shutting off the water is the need to install a tap on each pipeline, and their diameter may differ. Thus, the Neptune anti-leak installation has valve sizes from 1 to ½. More details about the available dimensions should be specified in the instructions for the specific device.
2. Controller for control. From here a signal is sent to the taps to shut off the water, after which a notification is sent to the owners of the bathroom. The unit can be connected to the sensor wired or wirelessly. The panel provides basic information about the state of the taps and the charge level.
3. Sensor. It can be autonomous or connected to the electricity network. The installation location is selected at a point with a risk of leakage.

As an addition, transmitters can be attached to control the device from a distance via Wi-Fi or with the ability to notify about the status of the water supply via SMS. The number of additional functions directly affects the cost of protection. Rich configurations are found in models with prices above the average level.

Rules for installing an anti-flood system

May differ when using different types of sensors - for example, wired and wireless. However, the basic rules remain the same - careful marking of points, sequence of arrangement processes, connection for verification after assembly.

Ball valve insert

After the water is turned off and the water meter is removed, the water supply is cut next to the blocked valve. This is the most difficult stage of the installation process and requires special tools and fasteners. Fasteners and tools depend on the diameter of the pipes and the material they are made of - locknuts or split couplings may be required.

The best places to install water leak sensors

The owner of the apartment probably already knows where in the communications system an emergency situation is most likely. The leak locations do not change, even if new plumbing is installed. If this is a new room, then the optimal place would be the transition between pipes or at the lowest point of the room, where the floor is sloped.

Controller installation rules

A zero and a phase must be connected to the device, and in order not to confuse which terminals the wires are connected to, it is better to use the instructions for use from the manufacturer, or number them for the convenience of the worker.

Checking the system operation

After the green signal lights up on the control module, the sensor plate is moistened with liquid from the tap. If all components of the sensor are correctly connected, an alarm will sound, a red light will light up and the water supply will stop. You can return the device to standby mode by removing the water from the plate and rebooting the device.

Classification of protection systems

Flood protection kits are not a new phenomenon and there are quite a lot of them. Despite the similarity in the principle of responding to a water breakthrough, these systems have a number of differences.

The main features of the classification of anti-leakage kits:

• how many shut-off valves are supplied in the set;
• what are the notification methods?
• how the sensors and the control unit exchange information with each other.

Number of shut-off valves

For example, the NEPTUN BUGATTI PROW and GIDROLOCK sets come with 2 shut-off ball valves

And the kit has only one tap.

It is logical to assume that there should be as many taps as there are risers for water supply in the apartment. But the total number of taps can be increased, depending on the nature of the room and the chosen anti-leakage system.

By signaling method

Methods for notifying a leak may also vary:

• the indication is simply displayed on the controller's light display;
• the same indication, but accompanied by loud noise signals;
• complex of noise alarm + light indication + sending SMS messages.

It is clear that sending SMS messages is possible if the system has a GSM transmitter. And this is very convenient if an accident occurs when the owners are not at home. Or an SMS message is simultaneously sent to the telephone number of the emergency service or management company.

If the system is connected to the Internet, it becomes possible to send group notifications via a GPRS connection.

By information exchange method

In the event of a leak, the sensors transmit a signal to the controller. There are two ways to transmit a signal - wired or wireless (via radio).

In the wired version, the sensor is under a constant voltage of 5 Volts. In normal condition, due to the huge resistance between the two contacts, no current passes through the sensor-controller circuit. When moisture enters, the circuit closes and an electrical signal is sent to the controller.

In order not to miss false alarms, and this is possible in wet rooms such as a bathroom, the controller is adjusted to the minimum threshold of passing current. If the specified limit is exceeded, the anti-flood system will be activated.

In wireless schemes, this response threshold is already set in the sensor itself. A special microcircuit continuously monitors the state of resistance between the two contacts and, in the event of an alarm, sends a radio signal to the receiving device in the controller. It is clear that both of these elements of the system operate on the same radio frequency.

But there is one problem.

The wireless small water leak sensor can operate over long distances (up to 200 meters). But different systems from different companies use their own principles of radio signal modulation. For this reason, a wireless type control sensor from a set of one system (for example, GIDROLOCK) cannot be replaced with a similar sensor from another set (for example, NEPTUN BUGATTI PROW).

But the best manufacturers of such alarm systems already supplement the kit with both wired and wireless sensors. If some sensors are missing, you can always purchase more.

Wired sudden water leak sensors are more attractive due to their simplicity and reliability. But a wired system can disrupt the design of the room, so there is a need for hidden wiring of cable lines. In addition, it is not always possible to connect a wired sensor.

Operating principle of leakage sensors

Speaking about the block diagram, everything is very simple. A certain element fixes the liquid at the point of its placement and sends a signal to the executive module. Which, depending on the settings, can give light or sound signals, and (or) give a command to close the valve.

How the sensors work

We will not consider the float mechanism, since it is not effective at home. Everything is simple there: the base is fixed to the floor, a float is suspended on a hinge, which, when floating, closes the switch contacts. A similar principle (mechanical only) is used in the toilet cistern.

The most commonly used sensor is a contact sensor, which uses the natural ability of water to conduct electrical current.

Of course, this is not a full-fledged switch through which 220 volts passes. A sensitive circuit is connected to two contact plates (see illustration), which detects even a small current. The sensor can be separate (as in the photo above), or built into a common housing. This solution is used on mobile autonomous sensors powered by a battery or accumulator.

If you do not have a smart home system, and water is supplied without any solenoid valves, a simple sensor with an audible alarm can be used as a starting option.

What types of SPPV are there?

Systems differ in:

• power supply method - from batteries, accumulator or mains;
• installation methods - some are installed during repairs, others can be installed after completion;
• type of valves - ball, ceramic, etc.;
• type and power of electric drives;
• type of sensors - wired and wireless;
• a set of additional functions - monitoring the status of batteries and taps, notification of events to the phone, remote control, etc.

Neptune

Hydrolock

Aqua guard

They offer options for apartments, country houses, offices and other premises. The basic set can be expanded with additional equipment.

System "Neptune"

It is produced in 4 versions. Prices for ready-made kits range from 9,670 rubles. up to 25900 rub.

Wired system Neptune Aquacontrol

for an apartment it has two 1/2" taps (or two 3/4" taps), two sensors connected by 0.5 m long wires to the base control module. This module closes and opens taps once a month, even if there is no leakage, to prevent them from souring. The system is powered from a 220 V network (there is no backup power source), the taps close 18 seconds after water hits the sensor. It is recommended to install it during repairs, since electrical wiring needs to be installed. 6 taps and 20 sensors can be connected to the control module. The warranty period is 4 years.

Wired system Neptune Base

has 3 sensors with 2 m electrical cords, two Italian Bugatti taps 1/2 or 3/4 inches, a basic control module. The crane motors operate no later than after 21 seconds and are powered by a 220 V network (there is also no backup power source). Recommended for apartments. Installation during renovation. The warranty period is 6 years.

Wired system Neptune Pro

differs from previous models in the control unit, which allows it to be integrated into third-party warning systems (dispatching, smart home, security systems), and the presence of a backup power source. Suitable not only for an apartment, but also for a cottage. 6 year warranty.

Wireless system Neptune Bugatti Pro+

— the latest development of the manufacturer’s designers. The system is equipped with two radio sensors, but 31 radio sensors or 375 wired sensors, as well as 4 taps, can be connected to it. Radio sensors operate at a distance of up to 50 m from the control module. When connected via a router, the signal reception range increases. Installed both during and after repairs. Suitable for large cottages with many possible water leaks. 6 year warranty.

GIDROLOCK systems

Operates on AA batteries. Options have been developed for use in apartments, country houses and cottages. More than 30 modifications are presented, taking into account the type of water supply - hot or cold individual or centralized, pipe diameter - 1/2, 3/4, 1, 1 1/4, 2 inches, room area and so on. The control unit monitors the performance of the sensors.

The control unit of the GIDROLOCK PREMIUM system is connected to 200 wired sensors, 20 ball valves, 100 radio sensors and a GSM alarm system that notifies about an accident via SMS message to the phone. The electric drive closes the tap within 12 seconds from the moment the signal about a leak is received.

There is manual control of the position of the ball valve. It will be needed when there is no time to wait for the sensor to dry before opening the water, or if you need to turn off the water when no accident has occurred. For example, when replacing a valve in the kitchen. To do this, remove the metal clamp and turn the electric drive housing to close the tap. Open with a reverse motion.

The manufacturer offers kits for apartments and country houses with autonomous and centralized water supply. The electric drive housing is detachable from the ball valve, which simplifies the installation of the ball valve on the pipe.

System "Aquawatch"

It is positioned as the world's first flood protection system with triple power: from batteries, a universal network mini-USB adapter and a built-in uninterruptible power supply. It accumulates energy and ensures the operation of the system when the batteries are dead and/or when there is a power outage in the apartment. The system detects a damaged or lost sensor and gives a signal to turn off the taps.

The Autowatch-Expert model has the ability to integrate into the Smart Home system and connect a GSM module for SMS alerts.

How to make a water leakage sensor with your own hands

The assembly principle will differ depending on the model planned for installation. In any case, this is an alarm system that works according to one of three principles - wired, wireless, or more complex, with sensitivity adjustment.

Wired homemade sensor

Can be done using a simple electrical circuit and a signal wire connected to the control unit. The circuit works by closing the contact with water.

Wireless homemade sensor of the simplest design

Wireless works on the same principle, only the signal is supplied by energy coming not through a cable, but from an autonomous reservoir.

A more complex circuit with a sensitivity regulator

It can include several sensors and is used when it is necessary to monitor a larger area. In any case, the components of the design can be purchased separately at a radio store, and the diagram can be drawn up independently or looked at by specialists.

Homemade alarms

They are always much cheaper than factory-made products; it is not necessary to make them powered by electricity - for certain needs you can use float ones, or use someone else’s homemade developments.

How the device works

Various physical properties of water are taken as the basis for analyzing the presence of leaks.

Sensors that measure electrical conductivity between contacts are most often used to monitor the presence of leaks. Such a circuit, assembled independently, often replaces an industrial design. The contacts themselves are usually made of a foil-covered board, between which an insulating track is cut.

We also recommend that you learn about the faucet with a water switch, how it is designed, works and functions.

Types of water level meters

Wired modifications require wiring from the meter to the control unit. Advantages of flood sensors:

• no extra costs for sensor assembly;
• no need to use auxiliary power supplies.

One of the disadvantages is the presence of wires. They need to be hidden. It is better to hide the wires on the floor so as not to constantly touch them. The control device can be glued to the wall.

Many are afraid to use homemade sensors in order to be safe from a possible short circuit or, even worse, a fire. Therefore, they choose the more expensive option and buy ready-made controllers from manufacturers.

Wireless models do not require wiring from the sensitive component to the central unit. The flood controller can be installed in any place, as long as it is within the radius of influence of the wireless signal transmitter (300 m). Among the disadvantages: high price, the need to check batteries and change them (frequency - 1-2 years).

There are sensor models that can connect to the main security system.

The water flow regulator consumes almost no electrical energy to operate. The operating voltage of the devices does not exceed 9V. Therefore, there is no risk of electric shock.

DIY water flood regulator: materials and installation

Thanks to a simple device, you can design a wired controller at home. The water sensor consists of common components. Even if you have to buy some materials, it will still be cheaper to make a control device yourself than to buy it.

The sensor that you make at home only serves as a signal about a problem that has arisen. The device will not be able to stop the water.

Basic materials:

• 3 V battery (device CR1632).
• Transistor BC816.
• 1-2 MOhm resistor.
• Piezo emitter included with generator.
• An ordinary plastic bottle.

Step-by-step process for installing a flood regulator:

1. The first thing to do is study the design diagram.
2. Next, solder the resistor to the piezo emitter.
3. Then connect the transistor.
4. The circuit is connected to the batteries using blue electrical tape.
5. Then we proceed to the construction of the body. We take a large bottle from which we cut off the neck. The bottom is made on one side of the bottle, which is fixed with glue. We make two holes to insert the housing. You need to make holes in the lid for the piezo. Screw the cap onto the neck.
6. Now you can control the operation of the structure.

Wireless water leakage controller WD-102

The regulator is designed to establish the flooding of water or other electrically conductive, chemically inactive liquid.

The device consists of two parts. The plate itself, which is considered a sensitive component, and the control unit, which in case of an alarm sends a wireless signal to the GSM control panel. One battery will be enough to power the sensor. The duration of permanent work can be up to a year or more. Battery marking is 23A.

Inside the device there is an antenna for transmitting a signal over a distance of up to 100 meters of line of sight. This device is capable of transmitting a signal, including through walls. That is, the central unit can be in the next room. There are several jumpers inside the device, the so-called black jumpers. With their help, the alarm code is dialed when it is on the rear panel.

Then the code is typed using jumpers. They are black in color. Comes with a sensor. If there is no code on the rear panel, then you need to install at least one jumper in the same order as here. The jumper can be located anywhere, but one needs to be placed. The need for the jumper is that the sensor must have a code.

If the jumper is not installed, then the device will not be able to bind to the main GSM alarm unit.

An important element of the control device is a sensitive plate, which should be placed on the floor or any other surface where it is necessary to control water leakage. The sensitive component can be secured using a piece of double-sided tape. The plate is secured with a sensitive component to the bottom, and can be attached to the top with a plate of double-sided tape.

The sensitive component will be secured when you accidentally step on it. The control unit itself is also secured with double-sided tape on a wall or any other surface inaccessible to water. An exclusively sensitive plate comes into contact with water.

The flood sensor can be used to monitor the levels of different containers: aquariums, barrels and notify about their overflow.

A sensitive plate is installed at the required height and if it is overfilled, the contact closes and the sensor sends a red alarm.

General placement principles

Even a person without experience can handle the installation of the Akvastorozh system. You need to follow a few fairly simple steps:

1. Install electric cranes. Directly into the hot and cold pipes in the place behind the inlet valves. You need to close the inlet valves, then disconnect the water supply from them, insert the electric taps and return the missing part of the wiring (technical details will be described below).
2. Install the controller. Where it is dry and access is not difficult, for example, in a plumbing closet or in a hallway. Humidity in the room should not exceed 70%. The controller is easily attached using a special plate and two screws to any surface with drilled holes.
3. Place and connect leakage sensors to the controller. Installing wired sensors involves laying a wire (the seams in tiled floors are also suitable for this), fixing the bottom to the floor with a screw or double-sided tape, securing the plate to the bottom, and attaching a decorative cap. Wireless sensors do not require anything other than securing them with double-sided tape.
4. Connect other components to the controller. First the electric cranes, then the battery pack.

How and from what to make a housing for a signaling device

The housing for the alarm should be equally miniature. The most suitable size option is a lid from a liter milk can or from a package of soap bubbles.

The undoubted disadvantage of the device is the fact that the alarm will only help if you are at home. The beeper will not help in your absence. Here we need other means of control that are capable of transmitting a danger signal remotely. It won't be as cheap, but no less effective. The smart home system will help you control everything that happens on your territory, even if you are away. Here is an example of such a system:

Watch this video on YouTube

Think about how much easier your life will be with such devices. A little work and you will protect yourself from unpleasant surprises. What do you think about this? Do you use any devices to avoid leaks? Share your experience with our readers in the comments!

Water leakage sensor on K561LN2 chip

It works according to a scheme similar to the previous one, and also has high sensitivity and reliability.

Composition of parts

In addition to the humidity sensor and the K561LN2 microcircuit, you will need:

• bipolar transistor VT1 series KT3107D;
• resistors for 3 MOhm and 30 K - three pieces, 430 K - two, 430 K and 57K - one each;
• 100 microfarad polar capacitor for operation at voltages up to 16 volts;
• capacitor of 0.01 microns - two and 0.1 microns - also two;
• sound wave generator ZP-22;
• power supply 6÷9 volts.

Homemade sensor of the simplest design

Despite its primitiveness, the sensor is quite effective. Home craftsmen are attracted by this model due to the cheap cost of radio components and the ability to assemble it literally “on the knee”.

The base element (VT1) is an NPN transistor of the BC515 series (517, 618 and the like). It supplies power to the buzzer (B1). This is the simplest ready-made buzzer with a built-in generator, which can be purchased for pennies, or removed from some old electrical appliance. The power required is about 9 volts (specifically for this circuit). There are options for 3 or 12 volt batteries. In our case, we use a Krona type battery.

How the scheme works

The secret is in the sensitivity of the collector-base transition. As soon as a minimum current begins to flow through it, the emitter opens and power is supplied to the sound element. A squeak is heard. An LED can be connected in parallel, adding visual signaling.

The signal to open the collector junction is given by the very water whose presence needs to be signaled. Electrodes are made from metal that is not subject to corrosion. These could be two pieces of copper wire, which can simply be tinned. Connection points on the diagram: (Electrodes).

You can assemble such a sensor on a breadboard.

Then the device is placed in a plastic box (or a soap dish), with holes made in the bottom. It is advisable that if water gets in, it does not touch the circuit board. If you want aesthetics, the printed circuit board can be etched.

The disadvantage of such a sensor is different sensitivity to different types of water. For example, distillate from a leaking air conditioner may go unnoticed.

Based on the concept: an inexpensive autonomous device, it cannot be integrated into a single security system for your home, even a homemade one.

Homemade alarms

Almost anyone who has ever held a soldering iron in their hands can assemble a simple household electrical sensor that gives a signal when a water leak is detected; in any case, it will be cheaper than buying a finished product.

Note that we specifically emphasized the word “electric”. Before a system based on electromechanical shut-off pipe fittings became available to the general public, our craftsmen made many different mechanical devices with similar functionality.

A spring was used as the main mechanism, and an ordinary piece of paper from a school notebook was used as a leakage sensor. That is, when it got wet, it released the spring, which closed the damper. Below is shown such a mechanism in the cocked state and after operation.

Photo: triggered mechanism

We gave such a device as an example; it makes no sense to assemble it because of its low reliability, bulkiness and, in fact, archaic nature, and installing such a mechanism in a modern apartment will cause a lot of difficulties.

Now there are a lot of simple, more elegant solutions; below is a diagram of one of them.

Electrical diagram: autonomous leakage alarm

The principle by which this audible autonomous protection alarm works is quite simple: as soon as the water closes the contact (sensor), the buzzer (buzzer) is triggered and the LED turns on. The cost of the element base will be significantly cheaper than the price of a finished sensor with similar functionality.

How exactly the sensor will be implemented does not matter; it is desirable that the material used for its manufacture is resistant to corrosion (for example, stainless steel). Due to low power consumption, such a circuit can operate on AA batteries in standby mode for up to 3-4 months, when activated, up to two days (depending on the batteries).

Advantages of this scheme:

• low cost of the element base;
• The size of the assembled sensor is quite miniature, so there are no restrictions on its installation location. In particular, such a sensor can be installed under a bathtub or pipe on which a clamp is installed to ensure that the leak is completely eliminated;
• A correctly assembled sensor does not need adjustment.

Review and comparison of popular flood protection devices

"Stop Flood Rainbow"

An excellent domestic development with an electronic control unit, sensors and electric shut-off valves.

Aquawatch (aquastop)

It is considered a non-analog protective device that is triggered when the inlet hose breaks. Its installation will not interfere with the operation of the washing machine, but will avoid serious troubles if it breaks down. The manufacturer positions it as absolutely three: reliable, autonomous and safe.

Water leakage sensor on transistor 2N5551

This is the simplest, but quite reliable circuit that even a novice radio amateur can assemble.

Composition of parts

In addition to the humidity sensor, to operate the electrical circuit you will need:

• bipolar NPN transistor 2N5551 or one of its analogs: BC517, BC618, BC 879, 2SD1207, 2SD1853, 2SD2088;
• LED VD1;
• 3 volt power supply, for example, a flat lithium battery;
• three-volt piezo emitter;
• connecting wires.

All these parts are placed in a small plastic box, which serves as a housing, and are connected by soldering with a conventional soldering iron in a surface-mounted manner.

The principle of operation of the electrical circuit

The algorithm for triggering the leakage sensor is quite simple. In the dry position of the contact pads, transistor VT1 is closed and no current passes through its collector-emitter semiconductor junction.

When water appears in the humidity sensor, a short circuit occurs between the electrodes, the positive potential of the battery enters the base of the transistor and opens the transition from the collector to the emitter.

Current begins to flow through the piezo emitter and the parallel-connected LED. A sound and light signal is turned on to notify residents of high humidity.

The assembly and operation of a similar circuit based on the BC517 transistor can be seen in a short video by the owner of “Hands from the Shoulders”.

How the water leakage system works

• When water gets on the leakage sensor, the contact circuit closes and the signal about the leakage is sent to the control unit, after which, depending on the system you have installed, a sound alert is activated and the control unit performs the following actions:
• when connected to a pump block, it turns off the pump;
• sends a signal to connected external systems (for example, Smart Home systems, GSM informant, security alarms, Wifi informant);
• when electrically driven taps are connected to the block, they use them to shut off the water supply and/or heating

GSM leak alarm

A more complex circuit, with a sensitivity regulator

The cost of such a scheme is also minimal. Performed on the KT972A transistor.

The operating principle is similar to the previous version, with one difference. The generated signal about the presence of a leak (after opening the emitter junction of the transistor), instead of a signaling device (LED or sound element), is sent to the relay winding. Any low-current device, such as RES 60, will do. The main thing is that the supply voltage of the circuit matches the characteristics of the relay. And from its contacts, information can be sent to the actuator: smart home system, alarm system, GSM transmitter (to a mobile phone), emergency solenoid valve.

An additional advantage of this design is the ability to adjust sensitivity. Using a variable resistor, the collector-base transition current is regulated. You can adjust the response threshold from the appearance of dew or condensation to the full immersion of the sensor (contact plate) in water.

Controller selection

The brain of the system is the electronic control unit. Its main function is to accurately recognize changes in the signal level from the sensor and apply voltage to the actuator. It is important that the controller has a function for restoring from emergency mode after eliminating the cause of the leak. As you can see, the logic of the controller’s operation is quite simple, and therefore even the simplest devices, including homemade ones, can be used. In general, three options can be proposed.

Relay modules are the simplest class of control devices for connecting one or two sensors. There are a number of disadvantages: the lack of state saving when the power is turned off, the need to convert the signal from the sensor to the correct level and provide the circuit with a bypass with a manual reset to maintain it in emergency mode. However, this is the most budget-friendly option for constructing a circuit. Suitable solutions include Omron relay modules and Arduino expansion boards, as well as more expensive programmable relays such as ARIES PR110 for connecting up to 12 sensors.

Programmable relay ARIES PR110

Programmable logic controllers are the most universal type of control devices that make it possible to implement more complex algorithms for the operation of a leakage protection system and interconnect them with other automation complexes. For the same purposes, cheap single-board computers such as Arduino can be used, with the help of which functions such as forced drainage of water from the tank of a washing machine can be implemented.

One of the channels of the home automation or fire alarm controller can be used to connect a flood sensor. The only problem is a mismatch in the type or level of the signal at the sensor output, so it often becomes necessary to supplement the circuit with an amplifier or single-channel discrete converter.

An example of a leakage protection circuit on Arduino

The simplest control device can be made with your own hands from common electronic components. Amplification of the signal from the sensor can be implemented using transistors marked Logic Level (IRL series), which use very low voltages for control (about 2–3 V) and are capable of switching up to 20 A of load current. To avoid accidental operations, a 300–500 Ohm pull-up resistor is installed between the gate and source. It is advisable to supplement the circuit: limit the control signal with a zener diode to 50–70% of the maximum gate-source voltage, and also provide a shunt with a voltage divider between the source and gate to hold the switch in the open state. It is necessary to install an emergency reset button in the shunt circuit break. Such a circuit can have an almost unlimited number of transistors and, accordingly, control a number of actuators and indicators.

Water leakage sensor on K561LA7 microcircuit

It works according to a more complex, but quite accessible scheme, which has higher reliability and sensitivity.

Composition of parts

In addition to the humidity sensor and the K561LA7 microcircuit for assembly you will need:

• bipolar transistor VT1 series KT315G;
• 1 MΩ, 100 Ohm and kilo-ohm resistors: 1.5 K, 10 K, 300 K;
• two polar capacitors of 2.2 and 47 microfarads for operation under voltage up to 16 volts;
• 200 picofarad capacitor;
• Light-emitting diode;
• sound wave generator ZP-1;
• switch SA-1;
• power supply.

Analogues of K561LA7 are K176LA7, 564LA7, 164LA6, HFF4011BP, HCF4011BE, CD4011A, CD4011. The circuit is not critical to the level of supply voltage and operates reliably within its limits from 5 to 15 volts.

The principle of operation of the electrical circuit

When the dry contacts of the humidity sensor receive voltage from the power source, the LED does not light up and the sound generator does not produce signals: the emitter-collector transistor junction is in the closed state.

When current appears through the humidity sensor, current will flow through the chip keys to the base of the transistor and it will open. The LED will light up and an audible alarm will sound.

When the circuit is powered from the network and not from an autonomous source, it is better to move switch SA1 to the lower position. In this case, the LED will immediately light up, indicating that the leakage sensor is ready to operate, and it will go out when the transistor opens.

By changing the capacitance of capacitor C2, the tone of the sound generator is adjusted.

The current consumption of the electrical circuit is:

• approximately 1 mCa in standby mode;
• 25 mA when triggered.

DIY leak protection

Any person who is familiar with a soldering iron and has minimal skills as a radio electronics enthusiast can assemble an electrical circuit that operates on the appearance of electric current in it when there is water between the contacts. There are many options, both simple and more complex. Let's give some examples.

The simplest method is based on the use of a transistor

The circuit uses a fairly large range of composite transistors (for details about which models we are talking about, see the image). In addition to this, the following elements are used in the scheme:

• power source - battery with voltage up to 3 V, for example, CR1632;
• a resistor ranging from 1000 kOhm to 2000 kOhm, which regulates the sensitivity of the device to respond to the appearance of water;
• sound generator or LED signal light.

Which sensor is better to choose for monitoring water leaks?

In this case, expert advice can be found in a variety of ways, but attention should be paid to each of the elements of the scheme. It is better to choose a controller that operates autonomously and is properly protected from external influences, with a minimum response time to danger. There are devices that are able to work with different components of the system and at the same time have backup power. You need to think about how to combine such recommendations with the simplicity and convenience required when installing the device yourself. Don’t buy the first one you come across, but carefully weigh all the parameters. The requirements for cranes are similar - compact, easy to install in the right place, with a suitable wire cross-section and the required length. Sensor – battery-powered or receiving energy from the controller. It is often recommended to buy a wireless water leak sensor - even an amateur can install it in the required location, which cannot be said about sensors with wires.

How to choose flood protection

The main characteristics of the complex's operation include the speed at which the valve is blocked. In the budget Neptune system, this figure is 0.5 minutes, while the technical capabilities of its analogue, Aquawatch, allow you to close the valves in 2-3 seconds. You can buy these products in Tyumen. When choosing a protective circuit, you should take into account that 20-25 liters of water can pour out of the pipes within 30 seconds after a rupture.

The cost of the kit increases when using wireless control sensors and additional taps.

Types of sensors, their design and operating principle

Water is the most important element of human life support. It is not surprising that many safety and protective systems have been developed, and the principles used vary. Even for use at home or at work, there are also separate models. There are also different ways to obtain energy - power supplies, accumulators, batteries, shapes and types of structures, connection location, number of standard elements, etc.

Float devices for monitoring liquid levels in tanks

Not particularly reliable in apartment conditions. They are much more often used in maritime affairs, on yachts or river fleets, although it is believed that this is a cheap and reliable way of signaling in places where water is constantly added from the central water supply system. However, they control only the upper level of liquid, so in everyday life they are usually used in toilet flush tanks.

Ultrasonic Water Leak Sensor

Sends sound waves of a certain frequency and receives a signal reflected from the walls of the container or the controlled thickness of the liquid. The peculiarity of the work is that the obtained value is constantly compared with the standard value; if discrepancies are detected, other devices that provide protection and transmit messages begin to work.

Electrode water leak sensor

The popularity of electrode devices is quite understandable - they work on the difference in electrical conductivity of water and air. It is enough to place the electrodes at the required distance to obtain a guaranteed signal if the electrode falls from air into liquid. Then everything depends on the reliability of the warning system.

Capacitive sensor for monitoring liquid parameters

Several variable electrodes can be installed for the container, allowing you to control the level of different parameters. Such sensors are good if you need to monitor not only leakage, but also several operating modes.

Radar water leak detection sensors

The operating principle is similar to ultrasonic ones. they also produce periodic signals at a certain periodicity and analyze the reflected vibrations. Even aggressive chemical compounds present in liquid form do not pose any obstacles to the installation of such devices.

Hydrostatic action sensor

Often used on an industrial scale, where constant monitoring of changes in liquid level is required. With the help of such sensors, it is possible to automate the supply of ingredients during the synthesis of chemicals or food preparation. The basis of the hydrostatic sensor is an element that is sensitive to changes in fluid pressure.

Some features of popular systems

In order to somehow highlight their protection against water leaks, manufacturers are trying to improve reliability or come up with other moves. It is impossible to systematize these features, but it is better to know about them when choosing.

Capabilities of one block

For different manufacturers, one control unit can control a different number of devices. So it won't hurt to know this.

• One Hydrolock controller can service a large number of wired or wireless sensors (200 and 100 pieces, respectively) and up to 20 ball valves. This is great - at any time you can install additional sensors or install several more cranes, but such a reserve of capacity is not always in demand.
• One Akastorozh controller can service up to 12 wired sensors. To connect wireless, you need to install an additional unit (designed for 8 Aquawatch Radio pieces). To increase the number of wired ones, install another module. This modular expansion is more pragmatic.
• Neptune has control units of different powers. The most inexpensive and simple ones are designed for 2 or 4 taps, for 5 or 10 wired sensors. But they do not check the functionality of the taps and do not have a backup power source.

As you can see, everyone's approach is different. And these are just the leaders. There are even smaller campaigns and Chinese companies (where would we be without them) that either repeat one of the above plans or combine several.

Additional functions

Additional ones are not always unnecessary. For example, for those who are often on the road, the ability to control cranes from a distance is far from superfluous.

• Gidrolok and Akvatorozh have the ability to turn off water remotely. For this purpose, a special button is placed at the front door. Go out for a long time - press and turn off the water. Aquawatch has such a button in two versions: radio and wired. Gidrolok has only wired ones. The Aquastore radio button can be used to determine the “visibility” of the wireless sensor installation location.
• Hydrolock, Akvastorozh and some Neptune variants can send signals to the dispatch service, security and fire alarm systems, and can be built into the “smart home” system.
• Hydrolock and Akvastorozh check the integrity of the wiring to the taps and their position (some systems, not all). In Hydrolock, the position of the locking ball is controlled by an optical sensor. That is, when checking there is no voltage in the tap. The Aqua Watchman has a contact pair, that is, at the time of testing, voltage is present. Protection against water leaks Neptune also monitors the position of the taps using a contact pair.

The hydrolock can be controlled using a GSM module - via SMS (commands to turn on and off). Also, in the form of text messages, signals about accidents and “disappearances” of sensors, broken cables to electric taps and malfunctions can be sent to the phone.

Always being aware of the condition of your home is a useful option.

On the issue of reliability: power supply and other issues

Reliable operation does not only depend on the reliability of the cranes and controllers. Much depends on the power supply, on how long each unit can operate autonomously.

• Aquawatch and Hydrolock have backup power sources. Both systems shut off the water before the backup power supply is completely discharged. Neptune has batteries only for the last two models of controllers, and then the taps do not close when discharged. The rest - earlier and less expensive models - have a 220 V power supply and no protection.
• Neptune's wireless sensors operate at a frequency of 433 kHz. It happens that the control unit “does not see” them through the partitions.
• If the batteries in the Gidroloka wireless sensor run out, the alarm on the controller lights up, but the taps do not close. The signal is generated several weeks before the battery is completely discharged, so there is time to change it. In a similar situation, the Aqua Watchman shuts off the water. By the way, the Hydrolock battery is soldered. So changing it is not so easy.
• Aquawatch has a lifetime warranty on any sensors.
• Neptune has wired sensors that are installed flush with the finishing material.

We looked at all the features of the three most popular manufacturers of water leakage protection systems. In short, the worst thing about the Aquawatch is the plastic gearbox on the drive; the worst thing about the Hydrolock is the high power of the system and, accordingly, the price. Neptune - inexpensive systems are powered by 220 V, do not have a backup power source and do not check the functionality of the taps.

Naturally, there are Chinese leakage protection systems, but you should choose them with caution. https://www.youtube.com/embed/EW3HuvRojwA

Leak sensor on LM7555 chip

This radio element is an analogue of the LM555 microcircuit, only with lower energy consumption parameters. Information about the presence of moisture comes from the contact pad, indicated in the illustration as a “sensor”:

To increase the response threshold, it is better to make it in the form of a separate plate connected to the main circuit with wires with minimal resistance.

The best option in the photo:

If you don’t want to spend money on buying such a “limit switch,” you can etch it yourself. Just be sure to cover the contact paths with tin to increase corrosion resistance.

As soon as water appears between the tracks, the plate becomes a closed conductor. An electric current begins to flow through the comparator built into the chip. The voltage quickly increases to the operating threshold, and the transistor (which acts as a key) opens. The right side of the diagram is the command-executive one. Depending on the execution, the following happens:

1. Top diagram. The signal on the so-called “buzer” (beeper) is triggered, and the optionally connected LED lights up. There is another use case: several sensors are combined into a single parallel circuit with a common sound alarm, and the LEDs remain on each block. When the sound signal is triggered, you will accurately determine (by the emergency light) which unit has triggered.
2. Bottom diagram. The signal from the sensor is sent to an emergency solenoid valve located on the water supply riser. In this case, the water is shut off automatically, localizing the problem. If you are not at home at the time of the accident, the flood will not happen, and material losses will be minimal.

Information: Of course, you can also make a shut-off valve with your own hands. However, it is better to purchase this complex device ready-made.

The circuit can be made using a printed circuit board layout that is equally suitable for both LM7555 and LM555. The device is powered by 5 volts.

Important! The power supply must be galvanically isolated from 220 volts so that dangerous voltage does not enter a puddle of water during a leak.

In fact, the ideal option is to use a charger from an old mobile phone.

The cost of such a homemade product does not exceed 50–100 rubles (for the purchase of parts). If you have old components in stock, you can reduce costs to zero.

The body is at your discretion. With such a compact size, finding a suitable box will not be difficult. The main thing is that the distance from the common board to the contact plate of the sensor is no more than 1 meter.

The operating principle of the devices that make up the system

To understand how all the components of the system function, you need to consider each separately.

Sensors

These elements are available in two types: wired and wireless. The first ones take power from the controller, the second ones need batteries.

The advantage of a wired sensor is energy efficiency, but such devices cannot be installed everywhere. For example, the installation location is too far from the controller, or it is impossible to extend the wire to it. Most often, the installation of both types of sensors is combined. The main characteristics are:

1. The number of possible water leakage sensors that can be connected to the complex. Most often, four are enough, but there are individual situations when additional devices may be required: then chains of sensors are created.
2. Easy to connect to the control device. It is convenient if the cables are equipped with connectors and there are corresponding inscriptions. This all saves time when installing equipment.
3. Number of devices included. Some manufacturers complete their water leakage monitoring systems with a minimum set of sensors. In this case, you will have to purchase additional elements.
4. Functionality. This could be the length of the cable, the ability to hide its wiring, protection from environmental influences, or simple replacement of damaged areas.
5. Operating distance of the wireless sensor. This point is important, since the distance of the device from the controller can be significant, or there are additional obstacles in the form of walls, ceilings, and so on. In this case, you must consult with the seller of the product.

Controller

The controller is the main control center of the system. There are a number of features of its operation:

Autonomy of the device in case of power outage. In case of severe flooding, the electrical wiring may short out, which means that the controller will fail and the electric cranes will not work

That is why it is so important that the main control center has autonomous power supply. Providing backup power for the device is very important, since even with a stand-alone version, the batteries may be discharged. An important condition is the ability of the control device to work with radio sensors. This is important because some rooms do not have the ability to run cables. Minimum response time to a leak

In this case, we mean the time during which the sensors and the controller itself react, and the electric tap closes. Monitoring protection against open circuits in the sensor circuit. This is an important parameter, since during operation the wiring can be cut off by children, pets or rodents. In this case, the sensor will stop functioning and the room will remain unprotected. The number of taps and sensors simultaneously connected to the controller. Most often these are four sensors and two electric cranes. But there are options when this is not enough, so the function of additional devices that the stop-flood system may have is important. Comfort of operation is an indicator of the charge level, indication when a leak occurs, self-cleaning of taps, the ability to temporarily turn off sensors, for example, for cleaning the room, an assortment of batteries for power that are easy to purchase.

Actuating (locking) devices

Another important element in the system is the electric crane

It is important that the leakage faucets used meet certain characteristics:

Tap closing speed. The amount of water that will flow in an emergency depends on this. The faster the closure occurs, the less damage the premises will receive. The compactness and overall dimensions of the taps - this affects their location in the plumbing system. Easy to install and dismantle

Since work with taps is carried out in a cramped plumbing closet, it is very important to ensure easy access to them. Material of manufacture: affects the service life and reliability of the device. The best options are brass or stainless steel. Electrical wire length

This indicator is affected by the distance of the crane from the controller. The thickness of the cable is important when installing anti-leakage and wanting to hide it from view.

General principles for placing leakage sensors

Any owner of a premises (residential or office) knows where the water supply or heating communications are located. There are not many potential leak points:

• shut-off taps, mixers;
• couplings, tees (this is especially true for propylene pipes that are connected by soldering);
• inlet pipes and flanges of a toilet tank, washing machine or dishwasher, flexible hoses of kitchen faucets;
• connection points for metering devices (water meters);
• heating radiators (can leak both over the entire surface and at the junction with the main line).

Of course, ideally, the sensors should be located precisely under these devices. But then there may be too many of them, even for the DIY option.

In fact, 1-2 sensors per potentially dangerous room are enough. If it is a bathroom or toilet, as a rule, there is an entrance door threshold. In this case, water is collected as if in a pan; the layer can reach 1–2 cm until the liquid spills through the threshold. In this case, the installation location is not critical, the main thing is that the sensor does not interfere with moving around the room.

In the kitchen, sensors are installed on the floor under the sink, behind the washing machine or dishwasher. If a leak occurs, it will first form a puddle in which the alarm will sound.

In other rooms, the device is installed under heating radiators, since water supply pipes are not laid through the bedroom or living room.

It would not be superfluous to install the sensor in a niche through which risers of pipelines and sewers pass.

The most critical points of water breakthrough

With uniform operating pressure, the risk of leakage is minimal. The same applies to mixers and taps, if you open (close) the water smoothly. The weak point of the pipeline system manifests itself during water hammer:

• when closed, the water supply valve to the washing machine creates a pressure that is 2–3 times higher than the nominal value of the water supply system;
• the same, but to a lesser extent, applies to the locking fittings of the toilet cistern;
• Heating radiators (as well as their connection points to the system) often do not withstand the pressure testing carried out by heating supply companies.

Peculiarities

The standard design includes an AL-150 water leak sensor (wireless or wired type), electronic actuators that shut off the fluid flow, and a control mechanism.

Installation of control elements is carried out in those places that are characterized by a high probability of liquid leakage, for example, under a washing machine or bathtub. The compact design allows you to be located anywhere and, as a result, control the entire space.

The functions of the control unit include providing sound notification of an incident and synchronizing sensors with electric drives.

Special taps equipped with a drive are characterized by an immediate response to a signal, after which the water supply is shut off. Among modern designs, electrically driven ball systems have become the most widespread. These elements are installed on liquid supply risers, usually after a manual tap.

The design and dimensions of the drives can be different; their purpose has a direct impact on the installation. Installation can be carried out at any suitable time due to the absence of the need for major intervention in the water supply system. But it is advisable to carry out work during the completion of repairs.