What to make a water level sensor. All about water level sensors. Making a float level sensor at home

Many summer residents use various water supply systems in their households that use intermediate containers. They help the water to purify, warm up, sand and iron oxides settle in them, the water is saturated with oxygen. Often such containers, barrels and tanks are installed in basements and using booster pumps. Or vice versa, they put them in the attic and the second floor, and then the water flows by gravity. But in both cases, it is desirable to know how much water is left in the tank. Especially if it is not equipped with an automatic water level maintenance system. To do this, you have to periodically go down to the basement or climb into the attic, which is inconvenient. And it is convenient to have a remote water level indicator with indication at the place of its main consumption or at the place where the control of the pump filling this tank is installed. Consider some device options that can be made in the country and remotely control the water level. It must be said right away that a person is hardly interested in the exact value of the amount of water in the tank. It doesn't matter if 153 or 162 liters are there. Here - just like in a car, it is important to know with an accuracy of 10-15% - "almost a full tank", "half", "less than a quarter", etc.

Mechanical indicators. The simplest in execution, but rather cumbersome. As a rule, they are a rather large and heavy float to which a cord is attached. The cord is thrown over a block (pulley) and a load is attached to its other end, approximately equal in weight to a float in the water. When the water level changes, the load moves up and down and can itself serve as an indicator of the filling of the tank, if visible. True, with an “inverted” scale - the more water, the lower the load-indicator.

But if the tank is not visually visible, then it is necessary to pull the cord to the location of the indicator. To do this, a strong cord is rubbed with soap (for better glide), passed into a thin tube and a scale is arranged at its other end. Of course, a scale the size of the height of the possible water level (and this can be a whole meter) is not required at all. Therefore, a pulley with a much smaller diameter is mounted on the same axis with the main pulley (and attached to the main pulley). A little cord is wound around it and it will already move the indicator needle. The length of the indicator scale will now be less than the stroke of the float as many times as the diameter of the small pulley is less than the diameter of the large one. And it will also be normal - the maximum level is at the top.

The same indicator can be made in the case of a float on the lever. Such a system is more suitable for tanks of shallow depth, but with a large surface area of ​​​​water. These are usually used to get rid of iron dissolved in water. In this variant, the required multiplication factor can be obtained simply by selecting the point of attachment of the cord to the lever.

A clear disadvantage of such indicators is the abundance of moving parts, and therefore the need to keep them clean and lubricated. The complexity of laying communications (tubes) over a long distance and through floors.

Pneumatic indicators. Such indicators are arranged as follows. A pipe is lowered into the water tank, which has a plug at the top. An air bell is formed in the pipe. A fitting is cut into the plug of the pipe, from which a thin sealed tube extends. At its other end is a U-shaped tube - an indicator. A tube from a container is connected to one of its ends, the other is free. The indicator contains a water plug (made of colored water). Thus, a certain portion of air is trapped in the tube.

When the water level in the tank changes, then accordingly this portion of air moves up and down. And along with it, the “colored” cork moves, which serves as an indicator. Unlike mechanical systems, there are no moving parts that require maintenance. But the system has other disadvantages. In particular, there are high requirements for the tightness of the tube and the dependence of readings on temperature and atmospheric pressure. The error is small, but it exists.

Electrical indicators. They are the most technologically advanced and can be performed in a wide variety of options. Starting from the simplest arrow indicators, ending with LED scales and displays. But at the heart of any electrical indicator is some kind of liquid level sensor. The easiest way to make it is from a variable resistor, the engine of which takes the appropriate position depending on the water level in the tank.

The connection scheme is quite simple. Any pointer head of a microammeter serves as an indicator. At the maximum water level (the variable resistor engine at the top of the diagram), by selecting the resistor R1, the microammeter needle is set to the extreme right position - “full tank”. This completes the setup. At a minimum water level (the resistor slider at the bottom of the diagram), the microammeter will show “zero” - “empty tank”.

Such a variable resistor can be mounted, for example, on the axis of a pulley (see mechanical indicators). And you can make it yourself. To do this, you need to take a wire made of metal with a high resistivity (nichrome, constantan, fechral, ​​etc.) and put a float on it with elastic sliding contacts. For example, from tinned sheet metal. The wire is hung in the tank, a load is attached below. Wires are soldered to the ends of the wire and sliding contacts. When the water level changes, the float will move along the wire from the maximum to the minimum level.

So that the remote indicator does not consume electric current in vain, it is better to connect it through a button. Then one set of batteries will last for several years. The use of a micrometer head is not the only indication. You can make a simple voltage comparator and use it with an LED scale, equip it with sound indicators, etc. Diagrams of such LED scales can be found on the Internet and the corresponding amateur radio literature.

The main convenience of electrical indicators is their accuracy, lack of transmission, ease of wiring, reliability, and spectacular display. The disadvantage is the need for power supply.

In industry and everyday life, there is always a need to determine the different levels in containers. For these tasks, level sensors of various designs are used. Depending on the filling medium of the tank, one or another sensor is used, sometimes, for the sake of simplicity and saving money and time, combined sensors are used, that is, they are made by hand. These are simple designs that use sensors of completely different types in their composition. Basically, such sensors are used where there is no easy access to the measurement environment or the measurement site is very aggressive for human health.

Types of level sensors

Most modern level sensors have an electronic relay with a converter in their design. The electronic circuit is designed to convert the measured value into a standard signal. The signal can be analog or discrete. Analog can be current 0..20mA and signal called current loop 4..20mA or voltage 0…5V, 0..10V.

Level sensors are used to protect the pump motor from dry running, they regulate the motors of pumps of wells that fill any containers with water and not only in the system of cold and hot water supply.

DIY water level sensor

Let's see, using the example of pumping water from a pit, how it is possible to make control in the automatic cycle of maintaining the water level not higher than it should be.

We have a pit with a very unclean liquid, consisting of water and coolant impurities for the cutters of a metal-cutting machine.

All types of sensors were considered, however, for the price and ease of execution, a combined design came up, consisting three meters long wire(pit depth), attached to a float (a large plastic container with air), on the surface the wire is attached to a spring with a petal.

As a signal, a conventional discrete signal of 24V is taken from a conventional inductive sensor. He works on a petal. When the water level in the pit rises, the float rises, releasing the spring. A petal is attached to the end of the spring; it rises due to the unbending force of the spring. In turn, an inductive sensor works on the petal, feeding the pump motor relay to the coil, forcing it to pump water from the pit. In order to avoid frequent switching on and off of the engine, in the sensor-coil circuit, there is a switch-off delay relay with a setting of 10 minutes.

Thus, the next time the sensor is triggered, the relay will work again and the cycle will repeat.

Of course, to protect the engine from dry running, it is advisable put a leak sensor in the pipe through which the emulsion is pumped out. But in our case, the simplicity of the design was important. Instead of an inductive sensor, you can use two plates in contact with each other, which will be even more economical.

If the water or other liquid has a homogeneous composition, then you can apply the end who metric single electrode level sensor.

For example, DU-1N manufactured by "Relsib", designed to measure the level in various types of liquids. The sensor can operate over a wide temperature range. The case is not exposed to corrosion, consists of high-quality stainless steel. Ceramic and PTFE are used as insulation, which provides excellent insulation protection. Resistant to many mechanical loads. The measurements are independent of the density of the liquid. And does not require additional care during operation.

We will make a simple, but very useful and effective water level indicator ourselves. And this article will help you to do such a necessary and very useful thing.

First, let's look at the schematic diagram of this device.

Scheme of the water level indicator.

The circuit is very simple, but works great. At the end of the article there will be a video showing the operation of this water level indicator, which we will do together with you.
To get started, let's collect the parts that we need to make the device.

Details for the manufacture of a water level indicator circuit.

We will need:
Chip ULN2004 or similar, contact pad for installing the chip on the board. With such a platform, there is no risk of overheating the legs of the microcircuit with a soldering iron or damaging its internal structure with static electricity. And the repair of the circuit, if necessary, is reduced to a few seconds. It is enough to remove the burnt chip from the socket and insert a new one in its place. A solid benefit, especially for not very experienced radio amateurs.
Resistors R1 - R7 - 47Kom.
R8 - R14 - 1Kom.
LEDs of any color of your choice, with a diameter of 3 - 5 mm.
Capacitor 100Mkf 25v.
Terminal blocks of any type, or even without them, but the convenience of using the device will decrease somewhat.
Any breadboard, as long as all the components fit. I use such boards because I don’t want to bother with the manufacture of a printed circuit board, it’s just that it’s more convenient and more familiar to me.

The components are all assembled and proceed to the manufacture of our device.

We place some of the components on the board.
We immediately solder the installed parts, otherwise they will constantly pop out of the sockets.

Sealing parts one by one.
Install the following circuit details.

There is no system, work as it is more convenient and easier for you.

You just need to constantly check with the scheme, no matter how simple it is. Everyone can get confused, but you don’t want to redo the work already done.

Accuracy and care, too, is not a superfluous thing.

And so in order. We install the part, solder it and move on to the next one.

We are approaching the finish line.

I installed the LEDs on the back of the board only because this water level indicator circuit block will be installed in the control panel on the front panel. The panel will be drilled under the LEDs, and the outlines of the container will be drawn on the outside. And the presence of the amount of water will be visually displayed on the shield. The board will be fixed with four bolts in the existing holes.

This is the first ready-made element of the future water purification system from iron, bacteria, all kinds of harmful impurities and other “kaki”. The system has been working at my house for almost three years, it has shown itself to be reliable, convenient, and in general I like it. I am completely satisfied with the quality of the water. But it's time for an upgrade. There are new requirements (for me), I want to have more convenient service, I want all the information about the system to be constantly in front of my eyes. I built the first water purification system without any experience and made some mistakes, which I will certainly write about in future articles, but in general there were only two minor breakdowns. I am to blame for one breakdown, and for another, it is not a high-quality component product (again, it is my fault, I saved a little and bought the wrong one).

All equipment will be modular (this increases the possibility of modernization and simplifies repairs), as cheap and simple as possible, so that many can repeat.

Why white wires are needed I will tell in one of the following articles.
The water level indicator (signaling device) is ready.

The cable that goes to the level sensors can be supplied with any eight-wire signal, they are now sold by all sorts and in different stores that deal with alarms and electrics. The cross section of the conductors and the length of the cable do not play a special role. There are cables that are very thin and cheap.

How to manufacture level sensors, you need to think and manufacture at the place of use. Sensor contacts are best made of stainless steel. The positive common electrode needs a massive one. I made from a small stainless spoon, the electrode works fine and does not lend itself to electrochemical dissolution at all. The places where the wires are soldered to the electrodes are best insulated with the help of any glue gun (they are securely preserved from dissolution).

However, if you power the circuit with a non-latching button, then there will be no dissolution. Need to see how much water - pressed the button. Released and the circuit power turned off. In the country, the circuit can be powered from batteries or AA batteries connected in series and with a button (enough for a long period) or from an old battery. This device is not demanding on the supply voltage.

Good luck to you.

In production, it is often necessary to measure the level of a liquid (water, gasoline, oil). In everyday life, it is most often necessary to determine the height of the water in a container; for this, special devices are used - level gauges and signaling devices. Measuring devices are divided into several varieties, they are purchased in stores, but for home use, the easiest way is to make a do-it-yourself water level sensor.

Types of sensors

Sensors differ from each other by the method of measuring the liquid level and are divided into two types: signaling devices and level gauges. The signaling devices monitor the specified filling point of the container and, when the desired volume of liquid is reached, stops its flow (for example, a float in the toilet bowl).

Level gauges continuously monitor the degree of filling of the reservoir (for example, a sensor on a mine drainage).

According to the principle of operation, water level sensors in the tank are divided into such varieties:

These are the most common level sensors, in addition to them, there are capacitive, hydrostatic, radioisotope and other types of devices that are used in various industries.

Selection rules

When buying a liquid level sensor in a tank, several factors must be taken into account, if they are observed, the device will work correctly and without fail. First of all, you need to determine fluid type and its density, the level of danger to humans. The material of manufacture of the container, its volume are of importance - the principle of operation of the selected sensor depends on these parameters.

The next point to pay attention to is purpose of the device, it will be used to control the minimum and maximum liquid levels, or to constantly monitor the filling of the tank.

When choosing industrial sensors, the number of criteria can be expanded; for household signaling devices and level gauges, it is enough to take into account the volume of the tank and the type of device. At home, do-it-yourself devices are used - they work no worse than factory models.

DIY manufacturing

The easiest way is to make your own float sensor of the water level in the tank, or a filling indicator.

The principle of operation of such a device It consists in the fact that the float floats in the liquid, at the maximum filling of the container it closes the contacts and signals a sufficient water level.

Manufacturing sequence:

The above scheme for manufacturing the sensor is the simplest; it is used for small containers.

The disadvantage of such a device is that it does not allow automatic shutdown of the pump. To stop the water supply to the tank, signaling devices are made using magnets and reed switches.

Hello. Today we will talk about a very simple kit for self-assembly of the device, to control the water level. This set can be successfully unsoldered by a 5-7 grade student in one evening. Of course, you can do it completely on your own, including the fee, but I decided to save time, so I ordered a set.

The set was purchased with the aim of at least somehow automating the collection of water in a barrel in the country. Moreover, this is not quite a barrel, but rather a pipe going down 2.5-3 meters, so there are decent water reserves there (for simplicity, let it be a barrel). The idea was simple, as long as there is no regular water supply, the electrovalve opens and draws water into the barrel at a given level. Water consumption by buckets as needed and automatic topping up into the barrel. In order for the valve to often not work from water fluctuations, several levels are conceived. The lower one at which the valve turns on and the upper one at which it turns off. Those. there is a certain dead zone in which there is a flow of water, but there is no water supply to the barrel yet. By the way, this dead zone is actually such a thing as hysteresis.
Last year, this function was performed by such a sorry device as a float mechanism from the toilet bowl. It worked properly, occasionally clogged, because the water comes through pipes straight from the river. But in the end, it did not survive the winter, because it was made of plastic and fell apart from frost.
This set was designed to replace the failed mechanism.

While storing the collected board and waiting for the summer season, an attempt was made to apply the collected board in production, on such an installation.


It's just a big pan with a 27 kW heating element type heater. The products are taken out of the refrigerator in whole pallets and placed in a pan. It is necessary to heat all this up to 90 C. Can you imagine how much electricity is spent daily?!

I will attach a couple of photos to estimate the volumes:

Products, among other things, are pork stomachs and curly (part of the intestines).
As far as I know, the stomachs are stuffed with something and eaten, with the intestines it’s about the same - including sausages with sausages.

This case is boiled and re-frozen. Then he goes to China. So, the cycle of goods in nature. We give them natural by-products, and in response, electronics ...

There was a question to transfer the heating of the pan to steam. So more economical and more powerful. Productivity grows exponentially. This is where a level sensor was required so that no one would be scalded by steam and steam was supplied only when there was at least a minimum amount of water in the tank.

However, I caught myself in time and refused the final installation, although the tests showed the board to work. It is contraindicated to use in the production of homemade products. Therefore, we found a less quickly needed device that performs the same functions, but also has a certificate. The principle of operation of a factory device practically corresponds to a set from an online store and, in a particular case, performs the same functions.
This device is of domestic production Aries SAU-M7.

Delivery and packaging:

Banggood is very stable, small package and several layers of polyethylene foam.

In a small bag there is a "bunch" of parts, a board and wires.


I didn’t sort by denominations, I just laid them out for clarity.


The scheme is not simple, but very simple. 4 elements 2I-NOT are used, and two of them perform the function of a trigger. It is needed to form a hysteresis loop.
Pins 1 and 2 of J3 provide a low level signal and turn on the relay. Contacts J4 1 and 2 - high level and emergency, when any of them is triggered, the relay turns off. The operation of the relay is duplicated by the ignition of the LED. The circuit works confidently on tap water and just as confidently on water after water treatment, in which there are fewer salts.
I assembled the board almost without looking at the circuit, except that I looked at the value of the resistors.
It is unlikely to confuse the conclusions and even install details such as connectors or transistors incorrectly prevent the applied silk-screen printing.
The only negative during installation - I mixed up the LEDs. But this is so, the little things do not affect performance.


Self-made level sensors of the conductometric type were used as sensors. This is how they look like assembled:

On the board from the installation side of the parts, silk-screen printing is applied, quite high quality.


The process of desoldering parts will not be of interest to you, since I am not an assembler and do not own the features of those process for assembling boards. What came into his hand from the edge, then soldered.
The printed circuit board on the soldering side is covered with a protective mask. There is no metallization. The payment is one-sided.

I used solder type POS 61 with rosin. Screwed up a little.


I fixed the power wires with sealant so that they would not break off at the exit from the holes. The wires that came with the kit seemed to me too short.


I washed the board with a solvent and alcohol and covered it with a layer of Plastik 70. I immediately noticed the difference between my previous boards and this one. The surface is shiny and the contacts are covered with a layer of film.
There was some inconvenience, which is actually a plus. I wanted to make a video about the operation of the board using a multimeter, but I got a problem in the form of the fact that the probes do not tritely push through the protective coating. Therefore, there is no multimeter in the video.

Video demonstration of the board:

Update: while writing a review, I didn’t even pay attention to the product page, as usual. And only after writing a review did I pay attention to the product. The fee does not match the one that was sent to me and, judging by the comments, many are sent two different versions of the fee. This does not affect functionality. Both boards are functional.

Results: The simplest set, available for schoolchildren, also has a practical application. I recommend to buy. The sediment remained small due to the fact that the board came not the one in the description.

In my case, the wires turned out to be superfluous. They were probably planned to output LEDs from the board to the front panel and connect the power supply.

I plan to buy +52 Add to favorites Liked the review +25 +47