Types of hygrometers, the principle of robots, how to make a hygrometer with your own hands. How to make a hair hygrometer with your own hands. Homemade humidity meter How to make a hygrometer at home What are the pros and cons of a psychrometer

You can, of course, buy a thermometer-hygrometer, but it is interesting and cheaper to make it yourself. In view of the excess of free temperature sensors and some other parts lying around idle, I decided to assemble this device that I need in everyday life on ATmega168V and SHT21. Read more on…

In the circuit, the sensor measures not only temperature, but also humidity. For me, the practical use of this feature is doubtful, but since it might come in handy for someone, I decided to use it as well. By the way, this is probably one of my longest projects (software was written for a month!). The development was delayed mainly due to lack of free time and the buggy of some compiler, from some company, but first things first…

The thermometer does not have any exotic features - it just shows the temperature with humidity and a battery charge indicator. The display of data takes place on the screen from the Siemens phone. I wrote about how to connect it to the microcontroller earlier (link at the end of the article). I chose this display as the most economical display I have and it is very thin and easy to control with a microcontroller. The only drawback: at a voltage below 2 volts, nothing can be disassembled on it (although the controller works stably even at 1.8 V). That is why when the battery is discharged to about 2 volts, the battery indicator will be displayed on the screen.

I took the time to draw (or rather copy!) Big beautiful numbers to display the temperature and small strict numbers to display the humidity. What came out of it is clearly visible in the pictures.

Printed circuit board? No, have not heard:-). Yes, and why is she here if the details are one, two, and miscalculated. Good installation + high-quality case and nothing is scary for this device. Moreover, I do not plan to play football with them. All parts are connected with MGTF f-0.07 mm wire - the best mounting wire in the world :). Only it is difficult to clean it, but this is just its only minus. I don’t have any battery holder (due to the limited space in the case), so the wires were soldered directly. I used soldering acid as a flux, because I didn’t want to solder with rosin at a relatively low temperature of the soldering iron, and I didn’t dare to overheat the battery. All exposed contacts were carefully insulated with tape before shoving the whole thing into the case. I bit off the extra legs of the controller (with the exception of those that are needed for the firmware), and the case itself was glued with superglue. The display, by the way, also rests on it. As a result, the device looks much more beautiful from the outside than from the inside 🙂 It is also important not to forget to make a hole in the case for the sensor if we want to measure the temperature not inside the device case. The case itself is called G1906 (~$2), and this is how it looked at the very beginning of my mockery of it:

The most difficult thing here is to do just such a rectangular hole. I did this: first drawing a rectangle and then making holes along the contour with an ordinary drill with which I drill boards. After drilling 100500 holes, the rectangle breaks out, and the edges are cleaned with a file. By the way, this is perhaps the most even hole of all that I have ever done 🙂

Everything is quite simple and trite, except for a small highlight of power management. I spied it in some magazine: We close the button, the device starts, sets a logical unit on the leg, thereby maintaining the transistor in the open state, and after five seconds a logical zero appears on the leg and the transistor closes, cutting off the power of the entire device. Everything is ingenious and simple. Before use, you need to twist the resistor R4 so that at three volts of the supply voltage, a voltage of 1.1 volts is present on its brush connected to PC0. Otherwise, the charge level will not be displayed correctly. It is best to use a multi-turn resistor, it is easier for them to adjust tenths of a volt. The microcontroller operates at a frequency of 8 MHz from an internal oscillator. In total, the device consumes 5 mA, which means that the batteries (CR2032) will last for a long time.

And now we got to the most interesting part of the project: the software. Taking this opportunity, I would like to pour tons of hatred on the creators of the micropascal compiler. I have never seen such curvature. After my program began to occupy more than ~ 10kb of flash memory, inexplicable glitches began, which I skillfully overcame by stuffing various crutches. In my program, you can find unnecessary UART initialization (it doesn’t work without it), port settings through assembler inserts, and some other interesting things! I no longer write in micropascal, which is what I wish you.

Ready-made thermometers and thermometer-hygrometers can be bought, for example, here:

SHARE WITH FRIENDS

P O P U L I R N O E:

Recently, an old friend came to us. He lives in a private house and a couple of times unknown persons tried to visit him without an invitation. There is a need to install an alarm system. It turned out to be too expensive to put the house on the remote control. The best solution seemed to be to simply notify the owner with a call to the mobile phone when one of the motion sensors is triggered.

The most common and simple device for measuring air temperature and humidity during the drying of wood in drying chambers is an electronic psychrometer.

Principle of operation and brief description: The psychrometer consists of two thermometers: "dry" and "wet". "Dry" is just a thermometer, and "wet" is put on a cotton wick, the ends of which are lowered into a bath of water.

Due to the hygroscopicity of the fabric, the water from the bath rises and wets the entire wick. Due to the evaporation of water from the surface of the wick, the temperature of the "wet" thermometer decreases and a temperature difference arises between the "dry" and "wet" thermometers. This difference is called the psychrometric difference.

The lower the air humidity, the higher the evaporation rate, and hence the psychrometric difference. Thus, the "dry" thermometer shows the temperature of the air in the chamber, and the psychrometric difference characterizes the humidity.

Relative air humidity is determined by temperature and psychrometric difference using psychrometric tables. There are several tables, since the evaporation rate also depends on the air flow rate. For drying chambers, a psychrometric table is suitable for an air flow speed of 2 meters per second. As a rule, a psychrometric table is not used when drying wood, but simply set the temperature and psychrometric difference in the drying mode.

How to make a psychrometer

Option 1. An easy-to-make electronic psychrometer with a water supply system, made according to the principle of an automatic drinker, is shown in the upper photo on the left. It is made on the basis of two identical resistance thermometers. We recommend using copper thermometers (the letter "M" is present in the designation: M50, M100, and so on), since they have a linear nominal static characteristic. When choosing thermometers, pay attention to the environment in which they are intended. If the thermometer is designed for gaseous use only, water from the wick may seep into the thermometer and render it unusable. You need to take thermometers that are designed to work both in air and in water.

The "dry" thermometer is attached to the wall of the chamber with the help of a corner. For a "wet" thermometer, a stainless steel bath is made. You can use (if you have one) a ready-made bath made of heat-resistant plastic, aluminum, or another material that is resistant to corrosion. It is not recommended to make a bath from "ferrous" metal, as it will quickly rust, rust will "clog" the wick and the psychrometer will start to give incorrect readings of the psychrometric difference.

Do not make an unnecessarily wide or long bath. This will lead to an increase in evaporation from the surface of the water in the bath and you will have to add water more often, but you do not need it. If you find a ready-made bath, but it is too large, then make a lid for it with a slot for the wick.

"Wet" thermometer is installed at a height of 2-3 centimeters from the surface of the water in the tub. This height should not be made too high, as this will impair the wettability of the wick and the psychrometer will give incorrect readings.

The tank for pouring water into the bath is made from an ordinary aluminum canister. Do not use canisters made of polyethylene and other plastics with a low melting point. The temperature in the chamber rises to 70 - 75 degrees. At this temperature, the walls of the canister made of such materials soften, lose their rigidity, the canister simply flattens and almost all the water flows out of it.

The entire manufacture of the tank comes down to drilling a hole in the lid of the canister and installing a fitting on the lid (which is also bought at a hardware store). When installing the fitting, it is recommended to smear the edge of the hole in the cover with automotive silicone sealant. This will ensure the necessary tightness of the connection. A hose is put on the fitting, if necessary, the hose is tightened with a clamp - the tank is ready.

How and why does it work. Pour water into the canister, screw the lid tightly, lower the end of the hose into the bath and turn the canister over. Water will pour into the bath until it closes the hole in the hose, after which the flow of water stops. It's simple: the canister is airtight, water is poured out until the space vacated in the canister is occupied by air entering through the hose. As soon as the flow of air stops, the outflow of water also stops. In the future, due to evaporation, the water level in the bath will decrease, the hose opening will open and a new portion of water will pour into the bath. This will continue until the water in the canister runs out.

The main disadvantage of option 1. When drying the wood, a lot of water will evaporate from the bath. From our experience, 10 liters of water is enough for 3 - 5 days (depending on the size of the bath, the drying mode and its stage). That is, as a rule, there is not enough water in the canister for the entire drying, so you have to stop drying, open the drying chamber and pour water into the canister. By itself, this is not convenient and not desirable, and if the psychrometer is also located in a hard-to-reach place...
So if:

The drying chamber is located in a heated room.
There is a heated room next to the camera.
The psychrometer is installed in a hard-to-reach place.

Option 2 (middle and bottom photos). Everything is similar to option one, just another bath is added. This bath, together with the canister, is placed in an easily accessible place in the chamber (for example, near the technological door) or in a warm room outside the chamber. The bath of the tank (in the middle photo) and the bath of the psychrometer (in the bottom photo) are installed at the same level and are connected to each other by a hose. As a result, the water level in both baths will always be the same (property of communicating vessels). This option is a little more complicated and more expensive: you will have to make not one, but two baths, you will need to buy not one, but three fittings and more hoses. But ease of use will quickly outweigh the costs.

The main mistake with this option is that if the hose is not laid correctly, it “airs up” and water from the tank bath stops flowing into the psychrometer bath. The rule for laying the hose is simple: only one slack is allowed. If there are at least two of them, then an air lock may form in the upper part between them.

The advantages of option two are obvious: you can add water without entering the chamber and without stopping drying, at any time you can check the remaining water in the canister.

Water. Distilled water is recommended to power the psychrometer. When drying hardwood species with a long drying time, this condition is mandatory. When drying easy-drying rocks, some deviations are possible. If tap water is soft, then you can use it, but after each drying it is necessary to rinse the wick in running water. If the water is hard, softened water can be used. There are water softeners at any large boiler house, you can take water from them. What to do if the water is hard and there is no other? Collect rainwater in summer, melt snow in winter. It's not hard.

Wick. The wick should be made only from natural cotton fabrics: chintz, cambric, batting, and so on. You can use ordinary gauze rolled up in four layers.
It is recommended to check the condition of the wick before each drying. A clogged (salted) wick becomes hard to the touch. In this case, it must be removed and washed in running water (or replaced).
The wick should cover the entire working part of the thermometer. It is recommended to fix the wick on the thermometer, for example, with wire (see photos).

Location of the psychrometer determined by the design of the drying chamber. For the chamber described in the article "Requirements for the design of drying chambers", it is recommended to install the psychrometer on the chamber wall from the pressure side (from the side of the drying agent inlet to the lumber stack), at a height of about 1.5 meters, at the middle of the chamber length.

Special moisture meters are used. To date, there are needle, contact and chip modifications. In terms of parameters, they are quite different. However, there are not many manufacturers on the market for moisture meters. The main companies include EMSO and Valcom. There is an average good moisture meter on the market in the region of 1500 rubles.

How to do it yourself?

If necessary, you can make a moisture meter for wood with your own hands. Its circuit includes a dielcometric type sensor. Also, the device will require a compact generator. Its limiting frequency parameter must be no more than 30 MHz. Contacts for a home-made model are more expedient to select needle-shaped. Also, to make a moisture meter for wood with your own hands, you will need a three-channel type chip.

The device should be in the region of 3.5 f/m. The microprocessor for the model is selected with a pulse amplifier. Probes are most often used tubular type. The display is more expedient to select lowercase. Compared to text counterparts, it is simpler. Capacitive electrodes are used directly in moisture meters. In turn, the catcher will need to be installed resistive. Batteries are selected last for the model. In this case, you can use ordinary finger batteries.

contact models

Contact moisture meters for wood are well suited for working with plywood, as well as parquet. Additionally, in the construction industry, devices are used to determine the moisture content of panels. If we talk about contract features, then low-frequency generators are used in the devices. Directly the probes are installed tubular type.

The dielectric constant of most moisture meters does not exceed 3 F/m. The maximum temperature of this type of model is able to keep at 40 degrees. The display is used as a line and text type. Many modifications are equipped with temperature sensors. The calibration function is available on many devices. It costs an average of a high-quality moisture meter in the region of 2 thousand rubles.

Needle moisture meters

Needle moisture meters for wood are used, as a rule, for pine or spruce. The sensors in all configurations are of the dielectric type. If we talk about the parameters, then the measurement accuracy mainly fluctuates around 0.2%. The maximum humidity threshold of devices does not exceed 35%. The minimum allowable temperature for models is 0 degrees. Microprocessors in many devices are used with amplifiers. There is an average moisture meter for wood (needle) in the region of 1200 rubles.

Probe devices

Probe moisture meters for wood are mainly manufactured by the Valcom company. If you believe the opinion of experts, then their parameter is extremely low. Generators in devices are used with a frequency of 20 MHz. Directly traps are installed resistive type. The minimum moisture threshold for models does not exceed 5%. In turn, the devices are at level 1 PH. Displays are often used in moisture meters line type. Some modifications are equipped with thermometers. The calibration function in devices is quite rare. You can find a model of this type on the market for 2 thousand rubles.

Model EMCO AP

In the construction industry, the presented moisture meter is in great demand. It is ideal for working with parquets and panels. Also, this moisture meter is equipped with a thermometer. Another advantage of the modification can be safely called the presence of needle-type contacts. The manufacturer provides a three-channel microcircuit for the model, so the measurement of wood moisture is fast. The electrodes are capacitive type.

The maximum humidity threshold does not exceed 40%. In terms of dimensions, the specified moisture meter is very compact, and belongs to the class of portable devices. According to the documentation, its mass without batteries is 80 g. The resolution of the model is at the level of 1.3 pH. The maximum allowable temperature of the model is exactly 35 degrees. It is forbidden to use the presented device in frost. The measurement accuracy fluctuates around 1.4%. In stores, this device can be found for 2100 rubles.

Devices for determining moisture EMCO MP500

This moisture meter is equipped with a dielcometric type sensor. According to customer reviews, the resolution of the device is quite high. Directly the generator of the model is used at 22 MHz. According to the documentation, the maximum allowable temperature is 40 degrees. The display in the device is of the text type.

Batteries are used for 1 mAh, so they last a long time. In this case, the manufacturer provides a catcher of a resistive type. If you believe the reviews of experts, then there are no problems with determining the importance of chips. The maximum measuring depth is 10 mm. The user can purchase the presented moisture meter for 1400 rubles.

Model "Valkom EM4806"

The specified moisture meter for hardwood, among other models, is distinguished by a high resolution parameter at the level of 1.3 pH. All this suggests that the device works perfectly at temperatures below 10 degrees. In this case, the measurement accuracy indicator is at around 0.2%. The maximum allowable humidity threshold is 30%.

The catcher in the device is provided of a resistive type. The microcircuit is used three-channel, and the generator is set to low-frequency. According to the documentation for the device, the case is provided with the IP 62 protection system. The presented model weighs exactly 80 g. The moisture meter memory is enough for 30 thousand measurements. The user can buy it for 1500 rubles.

Reviews about "Valkom M804"

The specified wood moisture meter generally receives good reviews. The main advantage of the model lies in its compactness. If we talk about more constructive features, it is important to note that he uses probe contacts. There are two sensors directly in the case. Thus, the measurement accuracy is quite high.

The probe in the device is provided by the manufacturer as a tubular type. The resolution of the device fluctuates around 1.3 pH. The maximum moisture threshold, according to the documentation for the moisture meter, is 35%. Today you can buy this model for 2 thousand rubles.

Opinion about "Valkom AS101"

In construction safra, the presented moisture meter is in great demand. First of all, we should mention a high-quality generator, which is installed with a frequency of 33 MHz. In this case, the sensor is of a dielectric type. Contacts, in turn, are used needle-shaped. If you believe the reviews of experts, then the measurement accuracy of the model is high.

It can be used for parquet and panels. The minimum allowable temperature of the device is 0 degrees. The resolution index is 1 pH. The catcher itself in the device is of a resistive type. The microprocessor is used with a pulse amplifier. The maximum humidity threshold of the device is at around 40%. You can buy this moisture meter for only 1400 rubles.

Description "Extech MO280"

This portable moisture meter features a protected housing. The sensor he uses is of a low-frequency type. In turn, there are needle contacts. There is a calibration function in the presented instance. The ambient temperature can be determined using this device. It is also important to mention the high resolution of the model.

The measurement accuracy in this case is 0.3%. The maximum humidity threshold of the model is allowed at 45%. The microprocessor is provided by the manufacturer with an operational amplifier. Thus, data processing does not take much time. The memory of the presented modification is enough to make more than 20 thousand measurements. You can buy this moisture meter in the store for 1300 rubles.

Model "Extech MS60"

These wood moisture meters are often used by professional builders. They are able to work even at a temperature of 0 degrees. The body protection system of the model is of high quality. According to consumer reviews, the device is quite simple to use. Batteries for the model are selected with a capacity of 1.2 mAh.

According to many owners, they last for a long time. The probe of the presented moisture meter is of tubular type. The microcircuit in the case has a three-channel. This modification is equipped with a thermometer, and this pleases many buyers. If we talk about the parameters, then the measurement accuracy is at around 0.3%, and the resolution of the device is only 1.2 pH.

Do not operate the device at temperatures above 35 degrees. The maximum allowable humidity is 40%. These moisture meters on the market are sold at a price of 2 thousand rubles.

The level of humidity in the air of the environment can affect not only the well-being of a person, but also the condition of household appliances, furniture and products. The amount of moisture in the air depends on the climate of the region or man-made factors.

The norm for a healthy person is considered to be air humidity from 30 to 60%. To create an optimal microclimate in the room, special humidifiers or dehumidifiers are used, as well as air conditioners with automatic humidity control functions.

Use special instruments to measure:

hygrometers;
psychrometers.

A hygrometer is one of the measuring instruments, thanks to which you can determine the level of humidity.

Additional information: In 1783, the Swiss scientist Horace de Saussure designed the first hair hygrometer, but Leonardo da Vinci began working on the invention of this meter as early as 1400.

There are several types of hygrometers:

hairline;
weight;
condensation;
electronic;
electrolytic;
film;
ceramic.

Each of the devices has a special principle of operation. For example, the design of a hair hygrometer is a system of U - shaped tubes. They are filled with a special substance that absorbs water vapor. Air is pumped through this system by means of a pump and its humidity is determined.

The most accurate meter is considered to be a condensation hygrometer. It measures the amount of condensation that forms on a glass surface after being exposed to sunlight. The error in the operation of such a device is very low.

A psychrometer is another of the environmental humidity meters.

Types of psychrometers:

August psychrometer (station);
Assmann psychrometer (aspiration);
remote psychrometer.

The August psychrometer is one of the most well-known instruments for measuring humidity. The structure of this structure is quite simple. The design of the psychrometer consists of two identical thermometers attached to one stand. One of them is called dry, it shows the temperature in the room.

The second thermometer is called wet or wetted. The end of this thermometer in the form of a cover is wrapped with a batiste cloth or gauze, the end of which is lowered into a reservoir of water located on the back of the psychrometer.

If the end of a wet bulb bulb is dipped into a tank, it will indicate the temperature of the water there, not the air that circulates above it. Therefore, it must be taken into account that the distance between the vessel and the end of the measuring device should be about 3 - 4 centimeters.

The water on the cloth evaporates, causing the temperature on the wet bulb to drop until the thermometer shows the temperature at which the steam becomes saturated. At this point, the data displayed on the wet bulb will represent the actual ambient temperature.

Determination of air humidity in a certain room using a psychrometer takes a little time. To do this, the device is placed in a place isolated from sunlight and extraneous thermal influences for 10-15 minutes, after which the measurement results of each of the device's thermometers are recorded.

The thermometer scale is divided from - 25˚ to + 50˚ into intervals of 0.2 degrees.

How to use the psychrometric table

To determine the level of humidity based on psychrometer data, a special psychometric table is needed. The first column of the table shows the dry bulb temperature in ˚C. In the first line - the difference between the temperature readings of both thermometers. Relative air humidity is calculated at the intersection of the result of the first column and the first row of the psychometric table.

What are the pros and cons of a psychrometer?

The main advantage of the psychrometer is its simple structure. Accordingly, the determination of air humidity with a psychrometer is much easier compared to other measuring devices. Plus, it is much cheaper to manufacture than any other device.

But besides the positive aspects, the psychrometer also has disadvantages. The readings of this measuring instrument are greatly influenced by the movement of the surrounding air. That is, the higher the air velocity at the measurement site, the greater the difference in the final result of both thermometers of the psychrometer. This error was corrected in the aspiration-type psychrometer or, as it is also called, the Assmann psychrometer.

What is the peculiarity of the Assmann psychrometer?

The Assmann psychrometer is a much more complex and more reliable device for measuring air humidity. Both construction thermometers are located at the lower ends in a special metal case, which protects them from sunlight, thermal effects, and various damages. The air moves at a constant speed due to the operation of the fan. This fan, also known as an aspirator, blows the thermometers at a speed of 2 m/s.

Determination of humidity using this psychrometer: the device is suspended at the place of study at a height of 1.5 m from the floor; results are obtained in 10-15 minutes in winter and 4-5 minutes in summer.

The August psychrometer and the Assmann psychrometer have in common that both contain glass-mercury thermometers. The disadvantage of these devices is their fragility and, accordingly, the inability to carry out measurements remotely.

What is the difference between a remote psychrometer and other devices

A remote psychrometer is another example of a humidity measuring device. The design of this measuring device uses electronic devices such as a resistance thermometer or thermistors.

The main types of remote psychrometers:

manometric;
electrical.

A manometric psychrometer consists of one or two manometric type thermometers. In electronic psychrometers, as in all other remote meters, silicon transistors are used, which replace the sensors of dry and wet bulbs.

What is the difference between a psychrometer and a hygrometer

The main difference between these devices for determining humidity is the principle of their operation. The function of the hygrometer is to measure not only the humidity of the air, but also the humidity of various solids.

The indicators of a psychrometer, despite the simplicity of its design, are always more reliable, which is why in the notes to the instructions of some hygrometers it is recommended to check the readings on a psychrometer.

How to find out air humidity without measuring instruments

To conduct this experiment, you will need an ordinary glass, some water and a refrigerator. A glass of cold water is placed in the refrigerator for several hours. When the temperature of the liquid in the vessel reaches 3 - 5 ° C, the glass is placed in a room where air humidity will be measured.

If the air in the room is very dry, then condensation will be observed on the surface of the glass, which will disappear after 5 to 10 minutes of observation. If the air in the room is very humid, then large drops of condensate form on the walls of the glass within 5 to 10 minutes. If none of the two previous options is observed, the air in the room is of medium humidity.

How to make a do-it-yourself air humidity meter

The psychrometer is a fairly simple invention in its design, so anyone can make it on their own.

Necessary materials:

two alcohol thermometers;
a small piece of batiste fabric;
several wooden slats;
small screws;
glass jar.

To stand the psychrometer, you need to take a small wooden plate measuring 50 mm wide and 120 mm long. We attach a rail to it with screws, the length of which depends on the length of the measuring instruments used. Another bar is attached perpendicular to it, on which thermometers will be held.

For compactness and highest accuracy of indicators, thermometers should not be placed at a great distance from each other.

The base of the device can be connected to the stand by drilling a small hole in it, or you can use PVA glue. After the body of the psychrometer is assembled, the lower bulb of one of the thermometers is wrapped with a batiste cloth. The end of the fabric is lowered into a vessel containing a non-freezing liquid.

When checking the indicators of a manufactured device, you should check the results of the factory meter and compare both indicators. In the future, to determine the level of air humidity, it is necessary to use a special psychrometric table.

Using a minimum of materials and free time, the owner of the finished product will receive a useful tool for measuring the level of air moisture.

Collapse

A hygrometer is a moisture meter for an incubator, with which you can control the humidity of the air inside the case. But in different periods of incubation, the humidity indicators should differ: in the first week - 65-75%, in the second - 40-50%, in the third - 75% (data for hatching chickens are indicated).

Devices that are used for household incubators are characterized by low cost - from 500 to 1000 rubles per product.

Principle of operation

Electronic hygrometer

To measure humidity, lower the hygrometer for the incubator into the container through a special hole. It is fixed for 5-10 minutes in limbo.

After the specified time, the humidity readings should appear on the display of the moisture meter. In the case of opening the incubator lid to lower the device, you need to wait about an hour to get accurate data.

For long and productive operation of the device, it is protected from falls and bumps, do not pull the wire to which the sensor is connected.

In order for the device to function normally, it is necessary to observe the temperature regime (from -40 to +70 degrees). You should also reduce the likelihood of dust, dirt and various liquids entering the device.

The humidity sensor for the incubator works according to a certain algorithm:

If the humidity level inside the container has changed, which was set by the poultry farmer, the equipment works and signals possible problems.
After that, the farmer must study the moisture indicator, add or remove the amount of water in the incubator.
After a few hours, check the sensor readings again. You need to monitor it constantly so that the chamber has a stable level of humidity.

Types of hygrometers for an incubator

There are different types of hygrometers, which have their own characteristics, individual type of work, advantages and disadvantages.

There are the following varieties:

Weight hygrometer for an incubator. It consists of several combined tubes, which contain a hygroscopic substance that absorbs moisture. With the help of this system, some air is drawn in and its humidity is determined.
Hair moisture meter. It is known that hair changes length with changes in air humidity. Due to this, it is possible to measure relative humidity - from 30% to 100%. The hair is stretched on a metal frame, and if the humidity indicator changes, the data is transmitted to the arrow, which moves along the scale.
Film air humidity sensor for incubator. Equipped with a special organic film element. When the humidity rises, it expands, and when it decreases, it contracts.
Ceramic. Its work is based on the dependence of the resistance of a ceramic part on air humidity.

How to choose the right hygrometer, what to look for

To choose a good hygrometer for an incubator, you need to study its technical data. First, pay attention to the pressure parameter, which can be relative (RH) or absolute (g / m3).

The choice of equipment also depends on the size of the incubators. If the container is small, for 40-50 eggs, you can take the simplest device. But for incubators with 100 or more eggs, it is recommended to buy more powerful hygrometers.

Typically, hygrometer readings are wrong by about 5%. If you need a more accurate device, then optical views should be preferred. In order for the equipment to serve for more years, when buying it, you need to look at the level of its protection.

Measured on the IP scale. The higher the value, the more resistant the instrument is to dust, dirt and water.

Hygrometer Models

Instrument name	Price	Advantages	disadvantages
MAX-MIN	600 rubles	Equipped with a thermometer and an alarm clock. An additional sensor can be connected.	There are no disadvantages.
Digital moisture meter with remote sensor.	250 rubles	Humidity measures from 10 to 99%. Battery LR44 included. Using the device, you can work remotely.	Too high measurement error - 7-8%. Moreover, the device quickly fails.
Stanley 0-77-030	6000 rubles	Has a shock-resistant housing, LCD display, has a small size.	High price.
HP-2GD	600-700 rubles	Convenient interface, easy to use. Just press the button and select the desired option.	Poor quality of the body material.
Ryobi Phoneworks RPW-3000	2200 rubles	Combined with the work of a smartphone, data can be received directly on the phone screen.	There are no disadvantages.
DC-206	300 rubles	The model has a compact size, can be used in small incubators.	The case is easily deformed under mechanical influences.
HTC-2	600 rubles	It has a built-in thermometer and clock.	No.
TA308	700 rubles	3 in one: humidity sensor, clock and thermometer.	High error of indicators: above 5%.

If you are wondering which is the best of all options, then this title is occupied by the MAX-MIN device (3 in one). It's not just a humidity sensor. In the plastic case there is a thermometer for the incubator, which shows the temperature as accurately as possible. The device is also equipped with an alarm clock.

In addition, an optional MAX-MIN TH218A humidity sensor can be connected to it. By placing it right inside the case, you can not be afraid of violating the internal microclimate in the incubator.

The sensor readings are as accurate as possible with an error of 1%. If the humidity level changes, an audible alarm will sound, which will allow the poultry farmer to quickly learn about violations.

The thermometer lets you know if the temperature sensor is working properly. After all, if deviations from the norm are too large and quite frequent, then there is a high probability of problems in its functioning. It must either be replaced or properly adjusted.

An alarm clock is also an important and indispensable tool. Especially if you have to work with a manual incubator when you need to turn the eggs yourself. By setting it to fire every 4-5 hours, you will never forget that you need to perform masonry manipulations.

The screen of the equipment is large, divided into three segments (for humidity, temperature and hours). All indicators are visible from afar, highlighted in bright colors. Therefore, you do not have to approach the incubator every time, because the data on its work can be viewed from a distance. Particularly pleased with the cost of the device - only 600 rubles.

How to make a hygrometer with your own hands

And although the hygrometer for the incubator is inexpensive, you can make it yourself. A do-it-yourself moisture meter for an incubator gives more accurate indicators than its counterparts purchased in a store.

To make a homemade device, you must:

Take two mercury thermometers to measure air temperature, water. It is also necessary to take a board on which both thermometers will fit.
Both thermometers must be attached to the board parallel to each other. A vessel with distilled water is placed under one of them.
The mercury ball of one thermometer must be carefully wrapped with a cloth, without contact with it. Then the fabric should be tied with a thread, not too tight. This thermometer is called wet, and the second is called dry.
The edge of the fabric should be lowered into the water by 5-7 mm.
The indicators of both thermometers are compared with each other and, using the table, they find out the relative humidity in the incubator.

Sometimes you have to spray the eggs with water to increase the humidity in the chamber. But to resort to this technique should only be in the case of eggs of waterfowl. For the rest of the embryos, a moisture content of 50-60% is sufficient. You can calculate the moisture index using the table below.

Dry thermometer data	Temperature difference in degrees
	0	1	2	3	4	5	6	7	8	9
	Relative humidity in percent
15	100	92	80	71	61	52	44	36	27	20
16	100	90	81	71	62	54	45	37	30	22
17	100	92	81	72	64	55	47	39	32	24
18	100	91	82	73	65	56	49	41	34	27
19	100	91	82	74	65	58	50	43	35	29
20	100	91	83	74	66	59	51	44	37	30
21	100	91	83	75	67	60	52	46	39	32
22	100	92	83	76	68	61	54	47	40	34
23	100	92	84	76	69	61	55	48	42	36
24	100	92	84	77	69	62	56	49	43	37
25	100	92	84	77	70	63	57	50	44	38

←Previous article

Humidity is a vital parameter for the normal development of embryos in an incubator. In the first week of laying eggs, its value should be 60–70%, in the second - no more than 40–50%, in the third it should be significantly higher - at least 75%. This indicator can be measured with a special device - a hygrometer.

How does a hygrometer work

A hygrometer or moisture meter is a device that allows you to determine the level of humidity inside the incubator. To determine this value, the device is lowered into the container through a special hole for several minutes. After some time, indicators appear on the sensor screen. With the incubator lid open, you should wait at least an hour for accurate data.

Important!Drops, dirt and direct sunlight adversely affect the operation of the moisture meter. For the normal functioning of the device, it should be protected from the negative influence of the external environment.

Types of hygrometers for an incubator

Moisture meters can be of different types. Depending on the principle of their work, each of them has its own characteristics, certain advantages and disadvantages.

weight

The operation of this device is based on a system of tubes interconnected. They are filled with a hygroscopic substance that absorbs air. Absolute humidity can be calculated from the difference in weight before and after passing a certain portion of air. For this, a special formula is used.
The disadvantage of this device is obvious - it is quite difficult for an ordinary user to carry out the necessary mathematical calculations every time. The advantage of a weight moisture meter lies in the high accuracy of its measurements.

Hair

This type of device is based on the property of the hair to change length with changes in humidity. To determine this indicator, in the container of the incubator, the hair is pulled over a special metal frame.

Did you know?You can check the health of the moisture meter upon purchase by holding the device in your palm for a few seconds. Under the influence of the heat of the human body, the readings of the sensor should change.

It fixes the changes with the help of an arrow on a special scale. The main advantage of the method is its simplicity. And the disadvantages are fragility and low measurement accuracy.

Film

The principle of operation of this device is based on the property of an organic film to stretch at high humidity and shrink when its level decreases. The film sensor works on the principle of a hair sensor, only here changes in the elasticity of the film under the action of the load are recorded.

The data is displayed on a special board. The pros and cons of this method are identical to the characteristics of the hair moisture meter.

Ceramic

The operation of this device is based on the dependence of the resistance of a ceramic part, which consists of clay, kaolin, silicon and oxides of certain metals, on air humidity.

Important!To increase the humidity in the incubator, the eggs are sprayed with water. However, this should only be done with waterfowl eggs.

The advantages of this type of devices include their ability to measure humidity with high accuracy in a wide range, the disadvantages are their considerable cost.

How to choose a hygrometer for an incubator

When starting to choose, it is important to get as much information as possible about the technical characteristics of the device. When buying a moisture meter, the size of the incubator is also important - the larger it is, the more powerful the device should be.

When choosing a device, it is important to consider the following characteristics:

for models with a remote sensor, the integrity of the cable and display should not be violated;
the pressure parameter can be relative (RH) and absolute (g / m3);
if there is a need for a high-precision device, then an optical apparatus is ideal for this;
to place the device outside the living room, it is best to purchase a hygrometer with a high degree of protection from external factors, this indicator is measured on the IP scale.

The most popular devices are the "Chick-Chick" and "Max" moisture meters. Electronic devices for measuring humidity and temperature "Chick-Chick" determine the humidity from 20 to 90%, with an error of no more than 5%. Compatible with all household incubators. Moisture meters "Max" measure humidity in the range from 10 to 98%. Food - disposable batteries.

How to make a hygrometer with your own hands

At home, this device is not particularly difficult to make. Difficulties arise when using it - it requires certain mathematical knowledge and care to avoid errors in the calculations.

Tools and materials

To make a moisture meter you will need:

two mercury thermometers;
board to which these thermometers will be attached;
a small piece of fabric;
thread;
flask;
distilled water.

Manufacturing process

To make a hygrometer with your own hands, you must perform the following steps:

Two thermometers are attached to the board parallel to each other.
Under one of them is placed a flask with distilled water.
The mercury ball of one of the thermometers is carefully wrapped in a cloth, which is tied with a thread.
The edge of the fabric is lowered into the water to a depth of 5–7 mm. Thus we get a "wet" thermometer.
The readings of both thermometers must be compared and the air humidity determined using the temperature difference table.

Such a homemade device is a dubious alternative. First, the readings obtained in this way have serious errors.

Secondly, in order to take readings, it is necessary to constantly open the lid of the flask.
Which of the hygrometers will be chosen depends on the desire and capabilities of the poultry farmer. Today, they are offered a large selection of modern moisture meters: easy to use, with digital displays that measure not only humidity, but also temperature.

Did you know?Pine cones are a natural hygrometer. They open at low humidity and shrink at high humidity.

Relative humidity can be measured with a simple instrument called a hair hygrometer or hair hygrometer. The action of this device is based on the property of a human hair to lengthen with increasing humidity and shorten when it decreases. If you wish, you can make such a device yourself.
For this you will need:
- human hair;
- gasoline or acetone;
- hot glue;
- nitro glue;
- nails;
- carpentry and locksmith tools;
- drawing accessories;
- a sheet of plywood 5 mm thick;
- thick paper;
- steel wire;
- a rod from a ballpoint pen;
- a roller with an inner diameter of about 1 cm.
In the hygrometer, you can use not only hair, but also high-quality cotton thread.

Making a hygrometer

Take a human hair at least 40 centimeters long. The hair should not be dyed and in no case varnished. First of all, it must be degreased. To do this, wash your hair in water with washing powder (without conditioner) or boil it in a soda solution. You can also apply a rinse in gasoline or acetone. Attach a small plumb line to one end of the hair. It is best if the plumb line has a point. You can use the sharp end of a nail or the solvent-washed tip of a ballpoint pen to make a plumb line. It is important that the weight of the tip is sufficient to straighten the vertically hanging hair. To fix the plumb line on the hair, use hot glue or a drop of nitro glue. Pick up a small nail, put on it a piece of a ballpoint pen about 5 mm long or any other suitable plastic tube. It is important that the tube is free to rotate and not slip through the cap. The hygrometer is mounted on a vertical board or plywood panel with a horizontal base. Drive in the nail you prepared with a plastic tube in the center of the vertical panel so that the hair thrown over it with the free end can be attached to the horizontal base. The part of the hair thrown over the nail was about a third of its total length. Throw the hair over the nail and secure the free end with hot glue. When the humidity changes, the length of the hair will change, and the tip of the plumb line will rise and fall. Equip the hygrometer with a scale. It can be made from a strip of paper pasted on the dashboard behind the plumb line.

Hygrometer calibration

You can calibrate the hygrometer in the following way: bring the device into the bathroom, after turning on the hot shower in it. When the room begins to fill with steam, mark on the scale the lowest point against which the tip of the plumb line will stop as 100%. Next, place the appliance in a heated and cooling stove oven (not very hot so as not to burn the appliance). At the top point opposite the tip, put a mark of 0%. The 50% mark can be placed in the middle between the two extreme marks. You can carry out a more accurate calibration using a control hygrometer, but you can also calculate it, since the scale of a hair hygrometer is linear. If you could not get a long hair and the sensitivity of the device is not enough, equip the hygrometer with an arrow. Put a small pulley on the nail instead of the plastic tube. As a pulley, a roller from a curtain rod, a wheel from a toy car with a tire removed, you can also make it yourself. The main thing is that its diameter does not exceed 1 cm. In this case, the hair must be wrapped around the roller for one turn. Make the arrow out of a light material: elastic wire or a strip of plastic. Glue the arrow with hot glue to the end of the roller so as not to interfere with its rotation on the awn. In this case, the hygrometer scale must be made in the form of an arc or a sector of a circle.

Use special instruments to measure:

hygrometers;
psychrometers.

A hygrometer is one of the measuring instruments, thanks to which you can determine the level of humidity.

Additional information: In 1783, the Swiss scientist Horace de Saussure designed the first hair hygrometer, but Leonardo da Vinci began working on the invention of this meter as early as 1400.

There are several types of hygrometers:

hairline;
weight;
condensation;
electronic;
electrolytic;
film;
ceramic.

A psychrometer is another of the environmental humidity meters.

Types of psychrometers:

August psychrometer (station);
Assmann psychrometer (aspiration);
remote psychrometer.

If the end of a wet bulb bulb is dipped into a tank, it will indicate the temperature of the water there, not the air that circulates above it. Therefore, it must be taken into account that the distance between the vessel and the end of the measuring device should be about 3 - 4 centimeters.

The thermometer scale is divided from - 25˚ to + 50˚ into intervals of 0.2 degrees.

How to use the psychrometric table

What are the pros and cons of a psychrometer?

What is the peculiarity of the Assmann psychrometer?

What is the difference between a remote psychrometer and other devices

A remote psychrometer is another example of a humidity measuring device. The design of this measuring device uses electronic devices such as a resistance thermometer or thermistors.

The main types of remote psychrometers:

manometric;
electrical.

What is the difference between a psychrometer and a hygrometer

How to find out air humidity without measuring instruments

How to make a do-it-yourself air humidity meter

The psychrometer is a fairly simple invention in its design, so anyone can make it on their own.

Necessary materials:

two alcohol thermometers;
a small piece of batiste fabric;
several wooden slats;
small screws;
glass jar.

For compactness and highest accuracy of indicators, thermometers should not be placed at a great distance from each other.

Using a minimum of materials and free time, the owner of the finished product will receive a useful tool for measuring the level of air moisture.

Novice poultry farmers may not think that it is necessary to control not only the air temperature in the incubator, but also its humidity. In this case, it should be borne in mind that during different periods of incubation, the readings of the moisture meter will differ from each other. So, at the very beginning, air humidity should be maintained at a level of 65-75%, in the middle of the period it must be reduced to 40-50%, and at the withdrawal stage - 75%. Such a multi-stage approach will improve the hatchability of eggs several times over.

How to measure humidity in an incubator?

You can measure the humidity in the hatching box by using a special device called a hygrometer. The most common model can measure humidity that is in the range of 20 to 99%, while the error is only 5%, which cannot have a detrimental effect on the development of future offspring.

Most electronic devices designed to measure humidity in an incubator are equipped with a special sensor that is attached to a wire. This allows you to take measurements inside the case. At the same time, you can control the level of moisture by the scoreboard placed outside. It displays not only the percentage of humidity in the working area, but also the approximate temperature.

The ease of use of the hygrometer is particularly important. It is equipped with a switch that has two working positions: "on" / "off". It also has several buttons that switch temperature units. What a hygrometer looks like, you can see in the photo.

Humidity meters designed for home poultry breeding are relatively inexpensive. Its average price is from 500 to 1000 rubles per unit.

How does a hygrometer work?

To measure the air humidity inside the incubator, it is necessary to lower the sensor inside it through a specially made hole as shown in the photo. Fix it in limbo for 5-7 minutes. After that, the desired humidity indicators will appear on the display.

If you still had to open the lid of the incubator, then the real readings will be ready only after 40-60 minutes.
How to use the electronic hygrometer correctly?

In order for the device to work properly for many years, it is necessary to protect it from mechanical influences, in particular from shocks and pulls on the wire on which the sensor is attached.

Do not place the hatcher, and therefore the moisture meter, under the sun and in a draft. This can have a negative impact on future brood.

An important condition for the normal functioning of the device is the temperature regime, which can vary from -40 to + 70⁰С.

Keep the hygrometer away from liquid, dust and dirt. Particular care must be taken with the sensors and housing.

What to look for when buying a hygrometer for hatching chicks at home?

Before purchasing a device for measuring air humidity in an incubator, it is necessary to study the technical characteristics of all products on the market.

Pay attention to the measured pressure parameter. It can be relative (RH) and absolute (g/m3).
Consider in advance how many eggs will fit in the trays. Having decided on this indicator, tell the sales assistant about it, and he will help you make the right choice.
If you need a device with high measurement accuracy, then give preference to optical devices.
If you plan to place the device outside the living space, pay attention to the degree of its protection. It is measured, as a rule, on the IP scale. The values of this scale indicate the degree of reliability and the level of resistance of the device to water, dust and dirt.

As noted, the standard temperature regime of the hygrometer is -40 to +70⁰С. However, if you are going to operate it in other conditions, carefully study this indicator. Otherwise, you will not get the desired result - the chicks simply will not be able to hatch.

Is there an alternative to an electronic moisture meter in an incubator?

Despite the fact that a ready-made device for measuring humidity is not so expensive, some poultry farmers recommend making a device designed for the same purpose on their own. They explain this by the fact that the devices used for a homemade hygrometer give more accurate readings than their electronic counterparts.

How to make a homemade device:

To do this, you will need two conventional mercury thermometers, which measure air temperature, a board and water.
Thermometers are fixed along the edges of the board so that they are parallel to each other, and a container with distilled water is placed under one.
We wrap the mercury ball with a cotton cloth and tie it with a thread not very tightly.
We lower the edges of the fabric into the water by about 5 millimeters.
The indicators recorded by thermometers are compared with each other and compared with specially designed tabular data that are given in the description of psychrometers. For example, if the dry bulb reading is 37.5 degrees and the wet bulb reading is 26 degrees, then the relative humidity in the hatcher is 38%. Thus, the humidity of the air in the incubator is calculated.

Thus, the success of the hatching process is affected not only by the level of air temperature, but also by its humidity. The latter can be measured with a special device - a hygrometer, which can be bought at any pet store or made by yourself. However, the second option is rather laborious.