Automatic greenhouse with ventilation and watering. Greenhouse controller on Arduino

circuit diagram and an installation example in

greenhouse thermostat on the microcontroller ATmega8.

One way to heat greenhouses is to use electricity. With good and smart automation, you can ensure a high efficiency of the heating system, as well as ease of maintenance and automation in maintaining the set temperature. The efficiency of the greenhouse can be significantly increased by heating the soil and maintaining the air temperature. When developing this device a home-made electric boiler 5 sq. Two heating elements 2 + 3 sq. It is possible to use one heating element at a time, now it is warm outside, so one heating element copes well with the task. Heats a greenhouse 11 by 5 meters, height in the center - 3 m, double film, the greenhouse is deepened into the ground by one meter. The control unit monitors five points and manages three circuits. Two - a warm bed, room temperature. In the device menu, you can set your own temperature and hysteresis for each circuit. Separately for each circuit, day and night temperatures are set.

The thermostat also provides for monitoring the temperature of the coolant for emergency shutdown of the boiler in case of overheating, as well as the ability to connect a temperature sensor to monitor additional parameter(e.g. outdoor temperature). The transition time from day to night mode and vice versa is set in the menu and is common to all circuits. The operation of the pump is controlled by the automation unit. If the temperature has reached the set parameters and the boiler has turned off, the pump will still work set time and turn off. The pump is applied one general, on warm beds and on the room. warm beds and air temperature, controlled by solenoid valves, 12 volts. Schematic diagram of the thermostat:

This is what the photo looks like soldered board from the track side:

1.Instruction for the operation of automation

The thermostat microcontroller works with 5 DS18B20 sensors. The sensors are connected to one bus. It may be necessary to reduce R1. MK distinguishes sensors by their serial number. When manufacturing for the first time, you will have to randomly determine which sensor is responsible for what and install them accordingly.

Data is displayed in integer format, tenths are discarded, and trailing zeros are suppressed. Temperature range from -9 to +99 degrees. If the temperature is out of range or if there is a sensor error on the display -- instead of the readings of the corresponding sensor.

At the first connection, upon successful initialization of all 5 sensors, their serial numbers will be written to EEPROM. This will allow you to work correctly in the future if some sensors are dismantled or faulty. In case of replacement of sensors, it is necessary to erase the EEPROM and turn on the device. Erase EEPROM is currently possible only in the programmer. Then I can figure out how to do it through the menu. MK will work without quartz 8 MHz. FUSE must be properly installed. Indicator based on HD44780 processor.

2.Working with a thermostat

1. The MENU button cycles through the menu pages.

2.In the setup menu (Installation), the parameter available for setting flashes.

3.Set using the PLUS/MINUS buttons as usual.

4. Clock on DS1307. The time is displayed in the format hh:mm:ss. Display format 24 hours. Access to the clock through the menu. Time settings are available on the page - in turn: seconds (PLUS / MINUS buttons reset the value of seconds), minutes, hours. The time for turning on the day mode - day and night - night is set. For modes, the output format is hh:mm. Clock settings are stored in the DS1307 memory.

5. Transition from one parameter to another using the UP / DOWN buttons. The buttons work on a single press, regardless of the duration.

6. After 10 seconds from the last press, the settings will be stored in memory. The display will go to the main mode.

7. When you press any button, as well as when power is applied, the backlight turns on. The backlight will turn off after 30 seconds from the last button press.

3. Boiler control algorithm

1. When power is applied to the device, the controller polls the sensors, reads information from the real time clock. The controller compares the current time with those set for day and night modes and selects the appropriate settings for the operation of thermostats.

2. Approximately after 5 seconds the device is activated and starts to control the boiler.

3. If the temperature from the Pol-1, Pol-2 or Office sensors becomes lower than the set one, then the pump, heater is switched on and voltage is applied to the corresponding actuator for supplying the coolant to this circuit. When the temperature rises above the set value by the hysteresis value, the heater turns off, the pump remains in operation for 30 seconds to ensure that the heating element cools down to a safe temperature. To ensure the flow of water through the boiler circuit, the coolant supply remains open to this circuit for the duration of the pump operation. If the operation of the boiler is necessary for another circuit, then the coolant is switched off to an already unnecessary circuit immediately.

4. Emergency mode

1. If the temperature of the heat carrier exceeds the value set for the Boiler parameter, regardless of the state of the sensors, the pump is turned on, the heater is turned off, and the Office circuit is opened to ensure the flow of water through the boiler.

2. If the sensor of any circuit fails, this circuit is considered disabled, if the heater worked on it, then after 30 seconds, the pump and the circuit will turn off.

3. In the event of a malfunction of the heat carrier temperature sensor when the boiler is running, the device will switch the boiler to the mode as indicated in paragraph 4.1.

I had the idea to make an automatic greenhouse a long time ago. It came to implementation and I began to study greenhouse management and greenhouse automation. It turns out that an intelligent greenhouse is not so simple, there are a lot of subtleties that have to be taken into account. I'll probably start with the main thing - how growth and maturation occurs different cultures and what parameters environment should be supported during these periods.

Air temperature

If tomatoes and cucumbers grow in a greenhouse, then the environmental parameters for these crops are similar. Tomatoes feel good at air temperatures from +18 to +25°C during the day and not lower than +16°C at night. Soil temperature from +10°C and above. For flowering and fruiting, the temperature can be slightly increased so that the fruits ripen faster and are larger.
At night, substances from the leaves go to the fruits. If the temperature is increased, the fruit will more actively pour. If the temperature in lower limits, then this contributes to the growth of shoots and roots - for long-term fruiting.

To maintain the desired temperature in the greenhouse, it is necessary to take into account seasonal temperature fluctuations in the area where the greenhouse is located. If this southern part Russia, then you can focus on automatically lowering the temperature, and if Northern part Russia will also have to take care of the heaters.

So I'll start about ways to lower the temperature in the greenhouse. The easiest way to lower the temperature in a greenhouse is to create ventilation. For ventilation, "actuators" are used, which open the windows when the temperature rises.

There are autonomous "oil ventilators" - the essence of their work is simple, when the air temperature rises, the hydraulic oil expands and pushes the stem, thereby opening the window. When the temperature drops, it closes without any automation. But there are problems with them, the first problem is that if the air temperature is elevated and a cyclone suddenly flies with an increase in wind, the window may simply not have time to close and it may be torn off by strong wind currents. Well, the second problem is the flow of cylinders, but this can be noticed in time.

Greenhouse actuators

However, I decided to make the ventilation more intelligent. Linear actuators are sold in stores, with which you can open and close windows according to specified conditions. Because automation is always working, then ventilation can be connected to common system, because the actuator costs no more than a hydraulic cylinder, and the possibilities are much greater. In combination with a wind sensor, an atmospheric pressure sensor and a temperature sensor, you can expand the capabilities of your greenhouse. For example, an atmospheric pressure sensor can monitor pressure drops, because it has long been known that with a rapid drop in atmospheric pressure, a strong wind is more likely to pass, and already the wind speed sensor will accurately show that it would be necessary to close all the windows.

Air humidity

It's the same important parameter in the greenhouse, like the temperature, it should not fall below 60%. For different crops, this parameter can vary from 60% to 90%. Moreover, the parameter of air humidity varies depending on the stage of growth, flowering and fruiting. Therefore, greenhouse automation should provide the ability to change conditions or select already programmed programs for different crops and growth stages.

Ways to humidify greenhouses

Humidifiers and humidity sensors are used to humidify the air in the greenhouse, these can be ultrasonic humidifiers or atomizers high pressure. For ultrasonic humidifiers, reverse osmosis filters must be used, because. the piezoelectric element will quickly become unusable from the sun and other raids. But the nozzles of the high-pressure sprayer also become clogged, so a fine filter is needed.
For ultrasonic humidification, one fact should be taken into account, with ultrasonic humidification, the steam temperature is almost 40 degrees, i.e. when humidified, the overall temperature in the greenhouse will rise slightly. But ultrasonic humidifiers are an economical option, of course it is better to use a high pressure pump and special spray nozzles.

Soil moisture and watering

Another important parameter for greenhouses is soil moisture. In different stages of growth and maturation, this parameter changes. The greatest need of plants for moisture in the seedling period is up to 90-95%, as well as in the phase of fruit formation and fruiting.

Automatic watering systems

Automatic watering in a greenhouse is arranged differently, but in the end everyone comes to dosing watering. Soil moisture sensors can be used but with careful modification. Chinese humidity sensors from printed circuit boards can show accurate data for no more than a month, after which metal surface contacts are destroyed and oxidized. If you use this sensor, then eventually the moment will come when you go into the greenhouse and you have a pool there, everything is flooded and your plants will probably die. Therefore, humidity sensors can be used in conjunction with a water flow sensor (water meter). It is necessary to measure the amount of water consumed per day and set this parameter. The soil moisture sensor can be used but with modification, the contacts must be of a material that conducts electricity and oxidized as little as possible. It may be copper, but it also oxidizes over time, but this is already good, because. You can clean the contacts once a year and use again. But it is better to try graphite rods, graphite conducts electricity and does not oxidize. I have not tried it yet, but I want to make such a sensor for the test. In general, it is necessary to take the indicators of the water meter as a basis, and you can turn off irrigation with a humidity sensor if it shows the maximum values. For example, in rainy weather, the water flow decreases many times, and the set amount of water for the flow sensor can be too much. So it is better to make control for watering combined.

Watering is switched on by means of a relay by a signal from a sensor or by time. The container for watering should be at a height and it is better to do watering by "gravity" simply by opening or closing the solenoid valve. Thus, more can be done autonomous system, because a conventional battery is enough to power the controller and valves and solar battery. This principle of irrigation will be appropriate in places where power is often cut off for a long time.

soil temperature

Soil temperature - it is also important to regulate, because. Keeping the soil temperature within certain limits will help expand the capacity of your greenhouse. For example, in this way you can increase the time of use of the greenhouse from early spring until late autumn, and grow some exotic plants. Temperature control in an automatic greenhouse can be done with heating elements. The stores sell heating wires that are laid on the bottom of the beds. The heating is controlled through the controller, which constantly reads data from the temperature sensor, which must be located in the ground. Those. The temperature sensor must be waterproof. When the temperature drops, the controller will signal the relay to turn on the power for heating. As soon as the soil temperature reaches the set limits, the controller will turn off the power from the heater. To a heating element has not failed from frequent switching on and off, it is better to use special dimmers that will gradually apply a load to the heater.

greenhouse on arduino

Greenhouse equipment

1. Arduino Mega controller - aliexpress price $10
2. Relay block for 8 channels - price on aliexpress $ 10
3. DHT temperature sensors - aliexpress price $1
4. Temperature sensors DS1820 - aliexpress price $1
5. LCD I2C data display module - aliexpress price $3
6. Soil moisture sensors - aliexpress price $1
7. Light sensor - aliexpress price 1 dollar
8. Electro magnetic valves for drip irrigation - 150 rubles apiece in a car shop
9. Uninterruptible power supply unit for 12 volts without battery - 700 rubles, with a battery 2000 rubles.
10. Electric door lock drive for cars (for windows) - 250 rubles in a car shop
11. Float water level sensors - 200 rubles

Electrical load management

The Relay Shield board is suitable for controlling electrical equipment, the number of relays must correspond to the number of devices + a margin for the future, you can always add. The picture shows a 4 channel board. We will turn on / off the pump, electromagnetic taps. If you use a servo drive or an electric drive for a car door lock, you can open / close the windows.

Environmental parameters

The environmental parameters are read in the greenhouse using temperature and humidity sensors. This data can be used for ventilation.

Lighting control

You also need a photoresistor that will turn on the lighting.

Autowatering

The humidity sensor is needed for timely watering if the earth dries up. But automatic watering must be regulated by several sensors, because. the beds are usually long, and the sensor will not be able to provide accurate data for the entire area.

Timer

For additional automation circuits, you should get an Arduino clock board. For watering, it is worth using a timer in conjunction with an air humidity sensor. You can do a lot of things with a timer, and if you still use a calendar, you can increase or decrease the illumination interval depending on the requirements of plants of different crops.

Access to the greenhouse via the Internet

If you don’t want to limit yourself to only the offline version of the automatic greenhouse, you can buy a special network shield for 10 bucks on the same aliexpress so that you can control the greenhouse via the Internet. We can also use the network to connect video cameras. You can follow our plants via the Internet.

SMS alert

I don't want to get ahead of myself, here's an idea that came to mind. For example, if water is not pumped into the tank, the pump is clogged, or the window is jammed and the temperature in the room rises above 80 degrees, all this can lead to the death of plants. If we live in a country house, then we can look into the greenhouse once a day to see if everything is in order with the plants. But what if we are in another city? I think it is necessary to make a security algorithm to check the boundary parameters of the greenhouse. If one of the parameters approaches a critical point, you can send an SMS using the GSM shield for arduiono, it costs about 50 bucks for aliexpress. We will always be aware if our plants are uncomfortable, and we can call a neighbor to check if everything is in order with the greenhouse.

Airing

There are several ways to maintain the optimum temperature. for greenhouses, optimum temperature+22 degrees, maximum +30 degrees and minimum +16 degrees. To begin with, we will use an oil thermal drive, I don’t know the price, because. a specialized one costs from 1,500 rubles, but you can make it yourself from an old car shock absorber and additional capacity for better expansion. In general, the idea is this, when the temperature in the greenhouse rises, the oil in the thermal drive cylinder expands and pushes the piston, which is connected to the window, thereby opening it. And vice versa, as the temperature drops, the thermal actuator closes the window. If everything is calculated correctly, then electronic devices to maintain the temperature are not needed, but we will make a fully automated greenhouse, in case of extreme heat. And we will add more fans that will turn on if there are not enough oil thermal drives.

Watering

We have already read a lot about growing plants in a greenhouse, so we also do dynamic watering, and maybe adapting to certain plants. We get the main data for watering from humidity sensors, but sometimes it is necessary to specially make special watering according to the timer at the time of maturation or growth. To do this, we will write a script for a specific type of plant, but in the main we will use a humidity sensor. For irrigation, a large barrel is used, preferably dark in color, so that the water is heated in it, cold water cannot be watered. The barrel is placed at a height so that there is little pressure. A valve is connected to the barrel, which lets water into the dropper system. For complete control, it can be divided into sections with valves so that they do not overflow or underfill in different places, and use a separate humidity sensor for each section. Two water level sensors (minimum and maximum) must be inserted into the tank. According to these sensors, the pump will fill the barrel if there is little water there and turn it off if the barrel is full of water.

We bring it all to life with the help of the program

Once we come up with the exact scheme of automation, we can start programming sketches. The writing of the program is based on the C++ programming language. On the Internet you can find many examples that you just need to adjust to your tasks and change the numbers. At first, you will need to adjust the parameters and almost manually configure everything, and debug it in the process, so you will have to constantly monitor and adjust. It usually takes a couple of days, one to set up the second to check, but it would be better to be constantly aware of what is happening in the greenhouse at first, otherwise the sensor may not be there and respond poorly to changes. But then, when everything is debugged, it will be possible not to worry about the microclimate in the greenhouse, and just collect fresh vegetables and berries from the garden. Arduino programming is not difficult, there are many examples on the Internet. This lesson can be called a constructor for adults, fun and useful. The only thing I would like to say with all this is that arduino can solve everything, but for use in industrial scale or for high reliability, questionable. For reliability, it is better to use ready-made devices, although the arduino has been working for me for several years without problems.

Dear colleagues!
I would like to supplement the publications already available on the forum with a small article that complements the series affordable automation for suburban areas. STM32 as a series of microprocessors may well complement the group of automation devices built on Arduino.
A bit of history - why such a system was born at all. Most recently, I became the proud owner of 140 bushes remontant raspberry, and of course, made a landing. Despite the fact that efforts have been made, the result was deplorable. The landing was mulched and equipped drip irrigation- but more than half of the bushes turned out to be unviable by the fall. Moreover, surprisingly, no pests or diseases were noticed. That was the impetus for starting work.
First of all, a water analysis was carried out - and it turned out that the water has a composition that is not very well perceived by raspberries. Sad news - it says that without special system preparation, it is impossible to use water that is simply available in excess on the site. Of course, the Internet will help me - and the results are simply shocking ... ready system exceeds 270 thousand rubles, and you just can’t buy it - it’s made individually, and for my volumes the dormouse has too much productivity. It became a shame for the state - and now, after a year (!) of work, a system was born that successfully passed the tests and this year will manage the watering and top dressing of my plantings. And not just raspberries.
Actually, you rightly notice - this is open landings, and here the closed ground is discussed. Yes - the fact is that my colleague, who has 3 greenhouses, became interested in the project. And now controllers have been made for him in a small series, the photos of which you see below

A few technical details - a debug board with stm32f103c8t6 installed is used as the main board. Power supply 220V alternating current, there is a galvanically isolated RS485 bus and also a galvanically isolated 1-wire bus. The controller is freely programmable - it is fully compatible with the Mitsubishi FX2N controller by commands.
Supports Modbus RTU exchange protocol both master and slave. Also has a 2nd serial communication port - but only modbus RTU slave support.
Due to the presence of a 1-wire bus, it easily works with common DS18B20 temperature sensors. And it supports up to 128 pieces.
Also in this publication I would like to add a video of the operation of a system of 4 controllers operating via the modbus bus.

Why did I decide to post this? Yes, it's very simple - after all, not everyone can pick up a soldering iron and assemble what he needs. This controller makes it possible to realize any idea or idea of ​​a farmer without special knowledge.
A little chaotically described the system - excuse me. If you have any questions - you are welcome, I will answer as much as possible. Also, if this post is missed, I will publish materials on how this system will be installed in the greenhouse. I hope this experience is helpful.

Vitaly

Greenhouse controller on Arduino

This year I built a 30 sq. m. for tomatoes. Initially, I planned to cover it with polycarbonate, however, after weighing all the pros and cons, I decided to use a copolymer ethylene vinyl acetate film. Well, now that the season is ending, I can already say that I made the right choice and the greenhouse pleased me with quite a decent harvest (approximately, about one and a half centners). The dimensions of the greenhouse are 3.8 * 8, i.e., approximately 30 square meters. m. full area, of which approximately 24 sq. m. useful. Ventilation was carried out naturally through open doors and vents located at the ends of the greenhouse. Maximum temperature in a greenhouse at open doors and vents did not exceed the outside temperature by more than 5 degrees at the peak, although there are no vents at all on the side surfaces of the greenhouse. If I used SPK (cellular polycarbonate) to cover the greenhouse, the temperature would rise over forty in the absence of vents in the roof. In addition, the transparency of the used film, like that of a monolithic PC, is high - 92%, which ensured that the tomatoes bore very well and were clearly in generative mode due to the abundance of light. In SPC, although the transparency of each layer is approximately the same, the percentage of light passing into the greenhouse is significantly less - 92% * 92% \u003d 84%, plus part is lost on the partitions, which ultimately gives transparency no higher than 82%. As a result, plants receive significantly less light and go into a more vegetative mode, producing more leaf mass and less tomato. And besides, you have to constantly deal with the formation of the leaf mass, which is in excess due to the competition of plants due to lack of illumination.
In my greenhouse, due to the abundance of light, I didn’t have to cut the leaves at all, I only broke off the stepchildren, there were few leaves on the plants, and there were a lot of fruits. True, another problem arose - a light burn of leaves and fruits. On the leaves, this was manifested in the yellowness of young leaves, which formed shortly before the onset of heat, and on the fruits, in the appearance of white sides on the fruits from the side facing the sunlight. This factor had a very negative impact on the harvest, which could have been even much larger, and even led to the fact that the bushes did not retain their full-fledged appearance by autumn, and even the phytophthora tried. Then I still did not know anything about phytophthora - how it arises, which contributes to its spread. Then I learned that for a tomato, the cold is not so much terrible as the "bath" - when the plants stay for a long time during the day, like in a steam room, which occurs if the sun is already in the sky, and the greenhouse is completely closed. All summer I didn’t close the greenhouse at all, neither day nor night, regardless of any changes in the weather, the doors and vents were constantly open. However, closer to autumn, when, due to cold nights, the greenhouse must be closed for the night, when just fungal diseases begin to rage, and the temperature drops during the night and day, and consequently, the condensate increases sharply, the windows that are not opened on time can help you finish the season at once. This is exactly what happened to me - the whole day the tomatoes were almost "wet" at a temperature of 20-30 gr. and everyone fell ill with late blight due to the fact that any automation of ventilation on this moment I was absent, and I could not come to the greenhouse every day. As a result, I had to throw out 7 buckets of mostly almost red and pink ripe tomatoes.
Interestingly, despite the total disease with phytophthora, as soon as I eliminated the causes of the disease and began to monitor the opening and closing of the windows in a timely manner, the bushes began to continue to grow and grow more or less healthy fruits, so in September I almost removed almost all harvest. In October, we managed to remove about 8 additional buckets of fruit, and now about a hundred are still ripening there.
In what follows, I will continue to describe how I came to the conclusion that it was necessary to use automatic system temperature and humidity control and why it is better to make a control system based on a controller. Then I think to go directly to the project. In general, this topic is not about what has already been done, but about what I am just going to do - the topic is about further improvement of the greenhouse, and I firmly decided to develop and implement the system. If you want to participate in the discussion of this topic, you are welcome, for this it is not at all necessary to wait until I finish the presentation of this prelude, especially since, in general, it is not obligatory.

Registration: 06/23/13 Messages: 5.152 Acknowledgments: 5.780

Vitaly

Registration: 06/23/13 Messages: 5.152 Acknowledgments: 5.780 Address: Bryansk

Returned home, continue. Below you can see some photos of the construction of the greenhouse and the ripening of the crop. I had no seedlings this year - tall varieties were enough only for the extreme beds, and even then not completely, the rest was planted with undersized ones. Moreover, half of the tall ones and all the short ones were frozen on the window and they were delayed in development by almost 2 months. Planted seedlings on permanent place late - on June 1 and 2, and I covered the greenhouse only on July 21, and that was only because the weather on the street at that time completely deteriorated, it was cold, it rained continuously, so I had to cover it when strong wind and, just threw a film - it started to rain. And literally on the second day after the shelter, the weather changed dramatically and the heat set in. Tomatoes did not endure such a sharp transition very easily, given that in the evening, when I covered the greenhouse, I did not have time to make windows and doors, and the greenhouse stood completely covered until 12 o’clock the next day, while I arrived to finish it.
Literally after 2-3 days, I realized that I could not cope with a temperature of 30 in the heat, if only because it was sometimes up to 33 on the street. I thought for a long time about how to solve the problem, I really didn’t want to cover the greenhouse from the sun, because a decrease in illumination by 1% is equivalent to a decrease in yield by 1%, and in spring even more - the crop is lost by 1.5%. One of the options was to install sprayers on the roof of the greenhouse, which would work when the temperature in the greenhouse rises above 30 degrees, the other is to make 3 doors on each side, the possibility of which was laid down at the design development stage. Moreover, the doors were supposed to be made as openings into which frames could be inserted, tightened with anti mosquito net or frames wrapped in foil if it's cold, but I decided not to do this at the manufacturing stage.
I did not immediately learn that there is a very efficient way quickly lowering the temperature in the greenhouse with the help of foggers, allowing at the same time to adjust the humidity in the greenhouse. Now I decided to include foggers - foggers in the climate control system, and return to shading if for some reason this measure turns out to be insufficient to keep the temperature at 25-30 degrees. and eliminating the formation of white barrels on tomatoes due to a combination of strong light and high temperature though I think it will be ok.
Next, I will talk about my findings about what temperature regime it is necessary to provide tomatoes during the day for their normal growth and development, how this can be ensured and why ventilators based on hydraulic cylinders are completely unsuitable for these purposes.
And here are some photos:

Investments:

Last edit: 10/20/15

Registration: 06/23/13 Messages: 5.152 Acknowledgments: 5.780

Vitaly

Registration: 06/23/13 Messages: 5.152 Acknowledgments: 5.780 Address: Bryansk

Temperature regime

Based on the initial experience of operating a greenhouse this year, I concluded that there is no more important task in the process of growing plants in it than the task of temperature control. This is equally important for a greenhouse with any coating, even film, even SPC, even profiled polycarbonate. Of course, there are coatings in which this issue is practically not relevant - these are not transparent coatings, but coatings white color and mesh greenhouses, but we will not consider these options here. Moreover, in this topic, I decided to limit myself to considering the regulation of the parameters of a greenhouse made exclusively for tomatoes.
The fact is that each plant has its own favorite range of temperatures, humidity and other parameters. In order not to spread my thoughts along the tree, where I took these specific temperature levels required for tomatoes, which I will give below, I leave it to you, if the need arises, to check them and clarify them. I won’t even mention it again, but I’ll just copy what I said recently in this thread:

And what, in fact, is required to create at least some of the most primitive climate control in a greenhouse? For tomatoes, for example?
You just need to monitor the temperature outside and open the windows as early as possible in the morning, when the temperature outside rises above about 12 degrees, in order to dry the leaves and fruits from condensation, you need to open the windows and doors when the temperature in the greenhouse rises above 25 gr. and turn on the foggers when the temperature rises above 30, and turn on the heating of the greenhouse when the temperature in it drops below 12.
That, perhaps, is all. If you add some more automation, I'm afraid it will not be better, but worse. For amateur greenhouses at this level, this minimum is perhaps optimal, allowing you to get a decent harvest of healthy products, and not the crumbs that most now have.
And another snippet:
The question is how much is needed?
Not much, unfortunately. In order for something to be in demand, it is necessary, at least, to realize the need for it. And at what level many argue here with us, one can judge by a rather typical statement: My cucumbers grow in the same greenhouse with tomatoes and bear excellent fruit. Well, what can you explain to a person who is not familiar with the basics of agricultural technology? And since he has zero understanding of the need to maintain some kind of climate in the greenhouse, then, naturally, he has no demand for systems that support him. he will read it and say something, emphemic, like: “Tomatoes will be golden,” or maybe he will express himself more clearly and rudely, like: “The cat has nothing to do ... well, etc.
Many prefer to simply build complete sarcophagi for plants with complex underground systems storage of heat and laying out 200 thousand or more for them (no offense they will be told, they do this not for mercantile reasons), instead of installing at least the simplest system thermoregulation, and even claim that there is no other way (but this is already an offense).
And now let's look from the other side. There are people who are well versed in electronics and programming and they can easily make a very inexpensive control system, but I don’t see even one of them saying: For a tomato, you need to provide this, that, and that. And then their development could become very valuable for many, at least for those whose consciousness is not blinkered by the need to build sarcophagi - the same dinosaurs from the point of view automatic regulation, like an ordinary film tunnel, even though it was called pretentiously, say, "Ivanov's Solar Vegetarian".
Yes, that you need a special thermostat. If you use a separate device to control each individual parameter, it will not work either simply or reliably. I'm afraid that in order to implement the minimum I specified, one cannot do without a controller.

Yes, you will say, we will make a device in a minimalist form, and then it turns out that there is still a lot of everything to follow, alterations and rise in price will begin. Fortunately, software-based automation differs from rigid automation schemes in that it is not difficult to change control parameters and introduce new functions, and costs increase, basically, only by additional sensors and actuators, and only the program changes in the system itself. Therefore, it is quite reasonable, at the first stages, to limit as much as possible the number of functions performed by regulating only temperature and humidity, so as not to waste extra effort and money.
Humidity in a greenhouse is just as important a parameter as temperature, but these parameters are strongly related, therefore, by adjusting the temperature, we will also change the humidity at the same time, and not absolute, but relative humidity is important. For the sake of simplicity, don't overthink it for now, it's better to focus only on temperature control, but more on that next time where I try to list everything. necessary equipment for creating minimal system regulation and roughly estimate what it will cost.

Registration: 06/23/13 Messages: 5.152 Acknowledgments: 5.780

Vitaly

Registration: 06/23/13 Messages: 5.152 Acknowledgments: 5.780 Address: Bryansk

More about temperature

I was thinking, I should probably describe in more detail the reasons why the temperature in the greenhouse should be regulated exactly within the limits that I described above.
The fact is that the growth of southern plants at temperatures below 12 gr. generally stops, and if even lower, they begin to wither and cling various diseases, therefore, it is impossible to open the greenhouse when the outside temperature is below 12. On the other hand, in the morning, a lot of condensate collects on the leaves and fruits in the greenhouse. If you allow a "bath" when the bushes are wet, and the temperature rises to 20 and above - this is paradise for phytophthora - it's better not to. So you can ditch the entire crop very quickly. Therefore, you need to open the windows as early as possible. Summer in middle lane it's easiest to just not close the windows and doors at all, but somewhere in August, according to the weather, you need to switch everything to automatic.
The optimum temperature for tomatoes is 25 gr. If it rises higher, you just need to open the ventilation windows. If the temperature rises above 30 - this is fraught with damage to the leaves from overheating, sterilization of pollen, sunburn and other troubles, therefore, when reaching 30 gr. foggers should work - foggers that effectively lower the temperature by several degrees.
If the temperature in the greenhouse drops below 12 degrees, then this, I think, is already clear - I described it above - a heater of any type should be turned on. In the fall, when you just need to ensure the growing of the fruit that has set, I think you can lower this threshold of degrees to 6-10 in order to save energy. By the way, heating up to 40 degrees during the day is not so terrible, since the tomatoes are already at the stage of growing and the sterilization of the inflorescences is not terrible. If your tomatoes have already been infected, then such a high-temperature heating will kill late blight, therefore, for the purpose of disinfection, you can intentionally leave the greenhouse completely closed for several hours on a sunny day on purpose, only so that the temperature in the greenhouse rises, while above 30 gr. After that, the greenhouse must be thoroughly ventilated. Actually, I did just that, and maybe that's why the tomatoes in my greenhouse are still alive.
Well, perhaps that's all. Even if this is only realized, the plants will be in much more comfortable conditions and will give a much greater yield than in a greenhouse, in which the temperature jumps from 35 gr. in the afternoon up to 5 gr. at night. In any case, such an algorithm is quite suitable as a reliable basis, and there the question of further optimization will clear up by itself in the course of practical operation.

And now - about the minimum set of equipment that will be needed for the control system.

Controller hardware set

1. Controller - 1
2. Display unit (screen) for the controller - 1
3. Power supply 12 V for the controller - 1
4. Sensor outdoor temperature - 1
5. Internal temperature sensor - 1
6. heat gun - 1
7. Electric door drives (actuators) - 2
8. Electric drives of transoms (actuators) - at least 2, for greenhouses from SPK - more
9. Foggers (foggers) - for a greenhouse 8 m long approximately 8
10. Equipment cabinet - 1
11. Residual current device - 1
Well, to ensure autonomy, in the event of a power outage, the solar panel- and the battery - 1. And, along the way, there are still different little things, such as pipes for electrical wiring, the wires themselves, etc.
I don’t quote the cost of each piece of equipment now - it’s just like laziness and a little no time, anyway it will be gradually specified, they will be selected best options, suppliers, models, so I hope interested participants will help decide on this issue.

Last edit: 10/21/15

Vitaly, it is not clear to whom your very detailed statement is addressing. Judging by the fact that you chew the basics in detail, most likely for beginners, because everyone else, it seems, should be familiar with the above. The topic of greenhouse automation raised by you is undoubtedly necessary and important, but it causes some skepticism, the path you have chosen.
I do not pretend to be the ultimate truth, but as I see it, usually the project starts a little differently. First, goals and objectives are discussed and set, technical specifications are drawn up, appropriate solutions are selected. Sometimes even one small paragraph of the TOR crosses out the use of any solution methods, narrowing the scope of the available tools. So in a nutshell. You have already chosen the Arduino platform right away. Then explain why it is her, and not, for example, raspberry PI or something else. Arduino very elementary platform. Choosing it, you have to assign a very limited set of tasks to it, greatly narrowing your Wishlist. Until now, very elementary crafts have been done on it. There were regrets of enthusiasts working on it that it "does not pull" many tasks. Also, it seems that the set of sensors for it is very limited. I am not against automation and discussion, but, personally, for me, building a system on Arduino does not cause practical interest. So I'll be curious, maybe I'll go and read it and that's it.
Don't narrow the topic down to just one platform, don't discount the capabilities of other platform enthusiasts. Then the topic will probably be more crowded and useful solutions will appear more frequently.

P. S. If this topic was created only to describe your experiments with Arduino, then I apologize in advance that I got into the wrong place with advice. I'm already talking about what I want to have in the greenhouse, so to speak, the minimum technical specification that I see.

Registration: 06/23/13 Messages: 5.152 Acknowledgments: 5.780

Vitaly

Registration: 06/23/13 Messages: 5.152 Acknowledgments: 5.780 Address: Bryansk

Vitaly, it is not clear to whom your very detailed statement is addressing.
...as I see it, usually the project starts a little differently. ...You have already chosen the Arduino platform right away. Then explain why it is her, and not, for example, raspberry PI or something else. Arduino very elementary platform. Choosing it, you have to assign a very limited set of tasks to it ... Until now, very elementary crafts have been done on it. There were regrets of enthusiasts working on it that it "does not pull" many tasks. Also, it seems that the set of sensors for it is very limited. ...for me personally, building a system on Arduino does not cause practical interest. ...Don't narrow the topic down to just one platform, don't dismiss the possibilities of other platform enthusiasts. Then the topic will probably be more crowded and useful solutions will appear more often.
... I'm already talking about what I want to have in the greenhouse, so to speak, the minimum technical specification ...

In general, for every active forum member who writes comments, there are, judging by statistics, 200-300 just reading. Who are we referring them to? Are they newbies? Or are there many advanced ones among them who simply do not want to enter into a discussion that seems small to them, or do they simply not have enough time to participate in discussions? On the other hand, if there is a group that does not need to chew the basics, then we do not see their development in this area. Such discussions on this forum arose more than once, but the result is something not noticeable. I know only 3 examples of, perhaps, successful greenhouse automation. The first example - I gave the link above, the second one: I don’t remember, however, whether it really has an implementation on the microcontroller, and even SergeiL’s greenhouse runs under the control of a Samsung-based controller.

Naturally, I chose the Arduino platform for myself, and if I encounter difficulties in the process of implementing the system on it, I, as they say, will be responsible for this. But I immediately stipulated that I did not intend to somehow limit the freedom of discussion in this topic and was ready to discuss any aspects, except, of course, a simple blabbering of the issue. So please discuss any platform if you find a correspondent. I have already made a decision on what to stop, because if there is not a single one among those who have decided, then, accordingly, there will be no result in the end.

And about the fact that Arduino is a very elementary platform, I would like to clarify what you mean by this? Enthusiast opinion? Let's look specifically at what kind of enthusiasts are they and what did they try to do on Arduino before they came to this conclusion? Arduino is just a circuit oriented language, which makes it understandable to people who understand electronics. This is an open platform, so there are a lot of ready-made solutions, it is designed so that even non-specialists can start doing something for themselves using software technology, which led to the emergence of many such enthusiasts. Yes, it allows, but it does not exclude the need for a serious education, but this is exactly what enthusiasts often lack, which is why they begin to shift from a sore head to a healthy one. And therefore, before putting an end to Arduino technology, I would like to know what fundamental limitation of the capabilities of this language can you bring? Does he weigh a lot? The command system does not have functional completeness? Not enough speed? Extremely inconvenient in programming? What exactly?
I'll tell you a little secret. The thing is that you don’t have to do anything special in developing circuitry or programming for automating a greenhouse. This has already been done before us and greenhouses have been working for a long time and not just one person. You can just stupidly repeat everything without inventing anything, if this is enough for you and you don’t want to add something of your own. Get acquainted with the material, maybe you will change your mind about Arduino.

Registration: 03.11.13 Messages: 643 Acknowledgments: 690

Understood, I will not interfere in the discussion. I have a little more Wishlist from automation, which is why Arduino did not suit me, although, I repeat, my knowledge of it - superficial, learned from reading forums on this platform, may not be sufficient.

Registration: 06/23/13 Messages: 5.152 Acknowledgments: 5.780

Vitaly

Registration: 06/23/13 Messages: 5.152 Acknowledgments: 5.780 Address: Bryansk

Arduino very elementary platform. Choosing it, you have to assign a very limited set of tasks to it, greatly narrowing your Wishlist. Until now, very elementary crafts have been done on it. There were regrets of enthusiasts working on it that it "does not pull" many tasks.

Here is this topic to help you to fix your attitude to Arduino. As far as I, not a programmer, understood from a dispute between two programmers, claims against Arduino are not in the weakness of the platform. The claims were connected, as far as I understood, with her insufficiently high level, according to the opponent. However, a low level, you see, increases the power and speed of the language - any system programmer will tell you that. And the fact that the low level complicates the writing of the program, as he claims, is depending on whom. After all, Arduino is a language tailored for electronics engineers, so for them, as a specialized language, it will be much more convenient than universal. Another thing is for programmers who understand electronics rather poorly, but in languages high level they ate the dog - their opinion can therefore be understood.

Last edit: 10/21/15

Registration: 20.10.11 Messages: 887 Acknowledgments: 432

In my opinion, before arguing on what to build automation on, you need to decide on the technical specification, otherwise you will now push the industrial CNC into the greenhouse in order to open a couple of vents according to temperature. Although, again, if it is convenient for someone to work with one or another controller and there is an opportunity to use it, then why not, even if it is redundant. In any case, it is necessary to start with technical specifications and the construction of a control algorithm. So far, from the above, it follows that: below 12 turn on the heating, above 25 open the window, above 30 turn on the foggers. While the circuit is very simple, you can even do without a controller.

Registration: 06/23/13 Messages: 5.152 Acknowledgments: 5.780

Vitaly

Registration: 06/23/13 Messages: 5.152 Acknowledgments: 5.780 Address: Bryansk

... In any case, you need to start with technical specifications and build a control algorithm. So far, from the above, it follows that: below 12 turn on the heating, above 25 open the window, above 30 turn on the foggers. While the circuit is very simple, you can even do without a controller.

Well, try it. I'm not sure you can do it even with these. simple algorithm do without a controller. But you have already simplified the algorithm proposed by me, because I wrote that there are 2 sensors: one is in the greenhouse, the other is on the street, I just suggested the same threshold in both cases - 12 gr.

Do you think that it will be easy to implement even such a very simple algorithm in such an inertial object as a greenhouse? It can already be assumed that many obstacles will arise in the way of its implementation. For example, foggers instantly bring down the temperature at the top of the greenhouse, and overheating remains at the bottom, which means that intensive air mixing and additional sensors will be required with the complication, of course, of the control program. Humidity, too, cannot be increased uncontrollably - this will already begin to harm the culture, and effective reduction temperature becomes impossible. Therefore, it is assumed that in the future the algorithm and the entire system will become more complicated, it will be necessary to introduce fans for air mixing and for exhaust ventilation to reduce humidity.
It's just that much cannot be foreseen at this stage, especially since, for example, I have never done anything like this before. That's why I suggested the minimum difficult option which can no longer be made simple means e.g. with a thermostat. The meaning of this approach is that it is not difficult to complicate the device in the future. Therefore, now I would like to do the circuitry part - try to draw a diagram of the device core. The editor for drawing e-mail. I saw the schemes in the topic, which I already cited above. I already downloaded it myself, though I still have no idea how to work in it. It is difficult and long for one to move, especially when you don’t know much, so everything will go on very slowly. Today I spent the whole day choosing devices on the Internet - everything that needs to be bought, considered many options and, perhaps, did not the best choice, but the process has slowly begun.
The editor can be found here: sPlan- maybe someone is familiar with it or can advise the best one, but for now I'll try to use it.