Description of the operation of a Chinese thermostat for an incubator. Thermostats with air temperature sensor for incubator. Digital controller with two-position control

Incubation is a practical and simple method of hatching birds. Any poultry farmer knows that to be successful, you need to maintain a stable temperature and humidity. An automatic thermostat helps with this. It heats the elements so that the temperature in the incubator does not change, even if it changes sharply outside.

The number of birds hatched, their health and lives depend on how accurate and reliable the device is. But you don’t have to buy expensive thermostats in stores. Having the necessary parts, skills and knowledge in electrical engineering, you can make a temperature controller with your own hands. Such a device will be no worse than a purchased one.

How to make a simple thermostat for an incubator

There are two ways homemade device: using electronic circuit and based on a heating device.

The main thing you need to make a thermostat at home is a circuit. It will indicate the parameters of capacitors and resistors. Additional parts can be purchased at any electronics store. For the reliability of the scheme, it is important to take into account several nuances:

• To reduce, stabilize and filter the voltage, a resistor is used, not a capacitor. This will increase the service life of the regulator to 10 years or more;
• Do not connect lamps in parallel. It will be more reliable - series-parallel. This will eliminate the possibility of sagging and burnout of lamp filaments;
• Do not install a thermistor whose resistance is less than 1 kohm. This can degrade the performance of the circuit and reduce the stability of the thermostat;
• it is more reliable to use the K561LA7 microcircuit than an op-amp or PIC;
• a sensor that has a single-wire digital interface is used on a microcontroller;
• if you need an instant response of the circuit to temperature changes, you should use a thermistor with a non-metallic body. If you don’t need an instant reaction, you can use it with a metal case;
• The use of thermistors with negative and positive temperature coefficient of resistance is allowed.

Based on heating device

A thermostat based on a heating device is an effective method, but the disadvantage is that the sensitivity must be adjusted manually. The operating principle is as follows:

1. Disassemble an old heating device, such as an iron. Remove the thermostat from it.
2. Solder or wet the center so that the thermostat becomes inoperative.
3. Pour ether into the thermostat. With any change in temperature (even a fraction of a degree), the container will contract or expand. When the temperature rises, the plates will open (the air does not heat up), and when the temperature decreases, they will close (the air is heated).

ATTENTION: you need to work with ether carefully and quickly, as it is a volatile substance. It is very sensitive and affects the status of the thermostat.

1. Solder the thermostat.
2. Attach it to the device using the plate screws.

Connection to the incubator

For correct and safe work thermostat, it needs to be configured and installed:

1. Place the contacts at a distance at which the sensitivity indicators would be most accurate.
2. The thermostat is located outside the incubator.
3. The temperature sensor is left inside and located at a level slightly above the eggs. It is necessary to eliminate the influence of heating elements, lamps and fans on the sensor.
4. A thermometer is installed next to the temperature sensor.
5. The heating elements are located at least 5 cm above the sensor.
6. A fan must be built in before and after the heating device.

Tip: due to high humidity, it is better to put a tube on the thermistor and fill it with sealed glue. Repeat the procedure 2-3 times after the sealant has completely dried.

The thermostat will be a reliable device if the connections are carefully sealed and the terminals are tightly tightened.

Useful video

To make a homemade incubator, I needed to purchase a temperature controller. The requirements for it were: small dimensions, low cost, power supply from 12 V DC, a powerful executive relay (to withstand a significant load), indication of readings, setting parameters with control buttons, accuracy of temperature measurement and maintenance given parameters and of course reliability.

On the Internet I came across such a device - . Reviews about it met my requirements. Came to me from the Aliexpress website. This regulator can be used in many places - electric heating, incubators, refrigerators, drying cabinets, water heating systems, protection of electrical equipment, measuring the temperature of a car's coolant and then turning on the fan in a greenhouse, bathhouses, heated floors, heating pipes, etc... The regulator itself consists of an electronic board with 3 control buttons installed: SET The SET button serves to select a mode and set parameters, and with the and buttons you can directly change the data of the programmable parameters. The LED indicator has three digits. The temperature meter itself is based on a thermometer installed in a case and has a wire length of 30 cm.

The control limits lie in the range from -50.0 to 110.0 degrees. You can connect loads up to 15 A (at 12 V DC) and up to 5 A (when powering the load from 220 V network)

The device is powered by 12 -14 V DC. The measurement accuracy is within 0.1 Celsius. The regulator current consumption is 35 mA when the relay is operating: 65 mA. In my article I will tell you how to set up and slightly upgrade this thermostat.

The process of setting up the W1209 thermostat is shown in the video:

List of tools and materials
-knife or scissors;
-screwdriver;
- soldering iron;
-tester;
- a plastic tube from ear sticks or a pen refill;
- faulty LEDs with a diameter of 5 mm - 4 pieces;
- plastic stands - 4 pcs;
- connecting wires;
-12 V power adapter;
-screws;
-plastic box for screws with a transparent lid;
-adhesive tape.

Step one. Manufacturing of the body.

The disadvantage of the board is that it is not suitable for installation in the case; the buttons and indicator are located below the relay and terminals.

Step two. Installation of the electronic thermostat board.

I installed the thermostat board on stands made of a plastic tube (from a ballpoint pen) as close as possible to the top cover. We make button pushers from plastic tubes from cotton swabs or from the refill of a ballpoint pen. Then at one end of the tube we increase the diameter with a warm soldering iron and put it on the buttons. The tube sat tightly as it was expanded into a cone by the soldering iron.

Step three. Checking and adjusting the regulator.

I connected a 12 V adapter to power the thermostat (you can use any 12 V power source and a current of 0.1 A). I compared the temperature readings with a reference electronic thermometer, and as a result they turned out to be the same.

Setting modes.
P0 cooler or heater mode C/H
P1 hysteresis setting 0.1-15 degrees (difference in relay switching mode)
P2 setting the upper operating temperature limit
P3 setting the lower operating temperature limit
P4 temperature adjustment
P5 relay activation delay (0-10 sec.)
P6 emergency overtemperature. Mode P4 is used to adjust readings based on a reference device.

At this point all the finishing touches and alterations are completed. As a result, by mounting the board in a box, we protected the device from moisture and mechanical damage to the electronics and prevented people from being exposed to electric shock. After the modification, you can use the thermostat for its intended purpose.

In general, this is a good inexpensive device (100 rubles) with great potential in its field of application.

Thermostat w1209

I used the cheapest and most reliable thermostat.
I ordered a thermostat from an online store, here is the link-> AliExpress

Nutrition
The thermostat is powered by 12 volts
I used an antenna power supply

Video on how to set up a thermostat

Homemade housing for thermostat w1209 with 220 volt power supply

Connection diagram
Connecting the heater is very easy
If you are using a heavy load
you need to install an additional relay
see pictures

Description
The programmable thermostat is designed to control temperatures in the range from -50°C to +110°C.
It can be paired with a heater or cooler.
The programmable temperature regulator is equipped with a three-digit LED display, an LED indicator for relay activation, three control buttons, a connector for connecting an external temperature sensor,
terminals “K0/K1” for connecting the load and “+12V/GND” for powering the thermostat board. The LED display shows the current measured temperature. Preparing for work
1) Connect a 12V DC power supply to the “+12V” (plus 12V) and “GND” (minus 12V) contacts.
2) Connect the load to contacts “K0” and “K1” (connected to the open power circuit of the controlled device (series connection))
After supplying 12V power to the “+12V” and “GND” contacts, the LED display will display the current temperature measured by the remote temperature sensor.
Setting and adjusting the set temperature To set the control temperature, briefly press the "SET" button, then use the "+" or "-" buttons to set the set temperature,
and press the "SET" button again, or do not press any buttons for 5 seconds. Programming To enter the programming mode, hold down the “SET” button for 5 seconds, then use the “+” or “-” buttons to select the menu parameter code (P0…P6) from the “Thermostat Menu” table. Next, to configure the parameter, press the “SET” button and use the “+” or “-” buttons to change the parameter value. To save the settings, press and hold the “SET” button, or do not press any buttons for 5 seconds.

Indication
The LED display shows the following values
“LLL” - the sensor is not connected,
“HHH” - temperature out of range (less than -50°C or more than 110°C),
“---” exceeding the limits specified in parameter P6

Resetting parameters to factory settings

To reset parameters to factory settings (default settings): 1) turn off the power;
2) press and hold the “+” and “-” buttons; 3) Apply power to the thermostat.
The LED display will show “888” and then display the current temperature.

Characteristics

Dimensions: 40 x 48 x 14 mm
Temperature measurement and programming range: -50°C…110°C
Measurement accuracy: 0.1°C in the range from -9.9°C to 99.9°C; or 1.0°C outside this range
Control accuracy: 0.1°C 0.1°C range -9.9°C to 99.9°C; or 1.0°C outside this range
Hysteresis accuracy: 0.1°C Hysteresis: 0.1…15°C
Reading update time: 0.5 seconds Supply voltage, V: 12 VDC
Sensor: NTC 10K 0.5%, cable length 0.3 m, waterproof
Maximum load current: 5A / 220VAC; 15A/14VDC
Ambient temperature: -10…60°C
Ambient humidity: 20 - 85%
Current consumption: 30 mA Current consumption during relay operation: 65 mA
Load connection method: electromagnetic single-channel relay (5A / 220VAC; 15A / 14VDC)
(for larger loads, use a higher power contactor or solid state relay)

Successful incubation of poultry eggs is impossible without stable temperature control. The thermostat for the incubator must provide an accuracy of ±0.1˚С, with the possibility of changing it within the range from 35 to 39˚С. Most of the commercially available digital and analog devices meet this requirement. A fairly accurate thermal relay can be made at home, provided you have basic knowledge of electronics and the ability to hold a soldering iron.

In ancient times…

In the first domestic and industrial incubators of the last century, the temperature was regulated using bimetallic relays. To relieve the load and eliminate the influence of contact overheating, the heaters were turned on not directly, but through powerful power relays. This combination can be found in cheap models to this day. The simplicity of the circuit was the key to reliable operation, and any high school student could make such a thermostat for an incubator with his own hands.

All the positive aspects were negated by the low resolution and the complexity of adjustment. The temperature during the process must be reduced according to a schedule in increments of 0.5˚C, and doing this precisely with the adjusting screw on the relay located inside the incubator is very problematic. As a rule, the temperature remained constant throughout the incubation period, which led to a decrease in hatchability. Designs with an adjustment knob and a graduated scale were more convenient, but the holding accuracy decreased by ±1-2˚С.

The first electronic

The analog temperature controller for the incubator is somewhat more complicated. Typically, this term refers to a type of control in which the level of voltage taken from the sensor is directly compared with a reference level. The load is switched on and off in pulse mode depending on the difference in voltage levels. The adjustment accuracy is even simple circuits is in the range of 0.3-0.5 ˚С, and when using operational amplifiers, the accuracy increases to 0.1-0.05 ˚С.

For rough setting of the required mode, there is a jackal on the body of the device. The stability of the readings depends little on the room temperature and changes in the mains voltage. To eliminate the influence of interference, the sensor is connected using a shielded wire of the minimum required length. This category also includes rare models with analog load control. The heating element in them is constantly turned on, and the temperature is regulated by a smooth change in power.

A good example is the TRi-02 model - an analog thermostat for an incubator, the price of which does not exceed 1,500 rubles. Since the 90s of the last century, they have been equipped with serial ones. The device is easy to operate and is equipped with a remote sensor with a 1 m cable, a power cord and a meter load wire. Technical specifications:

1. Load power at standard mains voltage from 5 to 500 W.
2. The adjustment range is 36-41˚С with an accuracy of no worse than ±0.1˚С.
3. Ambient temperature from 15 to 35˚С, permissible humidity up to 80%.
4. Contactless triac load switching.
5. Overall dimensions of the case are 120x80x50 mm.

Numbers are always more accurate

Greater adjustment accuracy is provided by digital measuring instruments. A classic digital thermostat for an incubator differs from an analogue one in the way it processes the signal. The voltage taken from the sensor passes through an analog-to-digital converter (ADC) and only then enters the comparison unit. The initially digitally specified value of the required temperature is compared with that received from the sensor, and the corresponding command is sent to the control device.

This structure significantly improves measurement accuracy, with minimal dependence on ambient temperature and interference. Stability and sensitivity are usually limited by the capabilities of the sensor itself and the capacity of the system. Digital signal allows you to display the value current temperature to an LED or liquid crystal display without complicating the circuitry. A significant part of industrial models have advanced functionality, which we will consider using the example of several modern devices.

The capabilities of the budget digital thermostat Ringder THC-220 are quite enough for a homemade home incubator. Temperature adjustment within 16-42˚С and an external block of sockets for connecting the load allows you to use the device in the off-season - for example, to control the room climate.

For your reference, here is brief characteristics devices:

1. The current temperature and humidity in the sensor area are displayed on the LCD display.
2. The range of displayed temperature is from -40˚С to 100˚С, humidity 0-99%.
3. The selected modes are displayed on the screen as symbols.
4. The temperature setting step is 0.1˚C.
5. Possibility of adjusting humidity up to 99%.
6. 24 hour timer format with day/night division.
7. The load capacity of one channel is 1200 W.
8. The accuracy of maintaining temperature in large rooms is ±1˚С.

A more complex and expensive design is universal controller XM-18. The device is produced in China, and comes to the Russian market in two versions - with an English and a Chinese interface. Export option for Western Europe when choosing, naturally, it is preferable.

Mastering the device will not take much time. Depending on what temperature you want the incubator to be, you can adjust factory program using 4 keys. On 4 screens front panel displays current temperature, humidity and additional operating parameters. Active modes are indicated by 7 LEDs. Sound and light signaling in case of dangerous deviations greatly facilitates control. Device capabilities:

1. Operating temperature range 0-40.5˚С with an accuracy of ±0.1˚С.
2. Humidity adjustment 0-99% with accuracy ±5%.
3. The maximum load along the heater channel is 1760 W.
4. The maximum load on the humidity, motor and alarm channels is no more than 220 W.
5. Interval between turning eggs 0-999 min.
6. Cooling fan operating time 0-999 sec. with an interval between periods of 0-999 min.
7. Permissible room temperature -10 to +60˚С, relative humidity no more than 85%.

When choosing thermostats with an air temperature sensor for an incubator, consider the capabilities of your design. A small incubator will have enough control of temperature and humidity, and most additional options expensive equipment will remain unclaimed.

Do-it-yourself thermostat

Regardless of big choice finished products, many prefer to assemble a thermostat circuit for an incubator with their own hands. The simplest option, presented below, was one of the most popular amateur radio designs in the 80s. Simple assembly and an accessible element base outweighed the disadvantages - dependence on room temperature and instability to network interference.

Amateur radio circuits for operational amplifiers often surpassed industrial analogues in performance characteristics. One of these circuits, assembled on the KR140UD6 op amp, can be repeated even by beginners. All the details are found in household radio equipment from the end of the last century. If the elements are in good working order, the circuit starts working immediately and only needs calibration. If desired, you can find similar solutions on other op amps.

Nowadays, more and more circuits are made on PIC controllers - programmable microcircuits, the functions of which are changed by firmware. The thermostats made on them are distinguished by simple circuitry, according to functionality not inferior to the best industrial designs. The diagram below is provided for illustrative purposes only, as it requires the appropriate firmware. If you have a programmer, it’s easy to download on amateur radio forums ready-made solutions along with the firmware code.

The speed of operation of the regulator directly depends on the mass of the temperature sensor, because an excessively massive body has great inertia. You can “coarse” the sensitivity of a miniature thermistor or diode by placing a piece of plastic cambric on the part. Sometimes it is filled with epoxy resin to seal it. For single-row designs with top heating, it is better to place the sensor directly above the surface of the eggs at an equal distance from the heating elements.

Incubation is not only profitable, but also exciting. Combined with technical creativity, for many it becomes a lifelong hobby. Don’t be afraid to experiment and we wish you successful implementation of your projects!

Review of thermostats for incubators - video