Smart Greenhouse Ready-made Home Automation Project

In this review, I will tell you about my own example of creating a smart greenhouse based on the Seed project (Greenhouse), which uses Wemos D1 mini controller with the ESP8266 chip.

In this smart greenhouse I decided not to use all the indicators and devices, so I will list what is involved.

The next step is to develop a greenhouse project. This is my first greenhouse, so a small size of three by six meters was chosen. I took an eightieth beam as the main frame. A fiftieth rail was used for the lintels, doors and windows. And a two-hundredth board was used to tighten the frame. The structure will consist of six identical elements - posts with a ceiling and rafters. The first of them will contain a doorway, and the last one - a ventilation window. The finished drawings will look like this. The dimensions of the elements are chosen in such a way as to minimize the waste of lumber.

Well, after ordering and preparing the lumber, I started assembling. This is what the rafter element looks like. As a fastener, I decided to use brackets that are fixed with screws.

As for the greenhouse base, a small strip foundation with external insulation was poured for this. The main posts are installed on it, treated with mastic at the point of contact with concrete.

This is what the assembled greenhouse frame will look like. These are six elements fastened with a board and a lath.

For the roof, I decided to use cellular polycarbonate, which I laid on insulation to eliminate gaps and cracks. It is quite durable, does not bend and copes well with precipitation, including snow.

I decided to cover the sides of the greenhouse with oilcloth. This is a fairly cheap and practical method. Of course, the main thing is to fix it well.

The greenhouse itself is ready. Let's see what's inside.

First of all, these are the beds themselves. In my case, these are high beds. They warm up faster and are easier to work with. In total, I managed to place four beds.

In addition, a small concrete pedestal was poured on which a cubic barrel for water was placed. It is needed for two reasons. On the one hand, for watering with heated warm water, and on the other hand, together with its pedestal, it is a heat accumulator. Warming up during the day, it will give off heat at night.

Next to the barrel there will be a gas or possibly wood stove. As I already said, it will be heated on those days when there is a significant lack of heat, so as not to waste expensive electricity.

This is what one heater looks like. It has a power of half a kilowatt. There will be six heaters with a total power of three kilowatts. They will be switched on via a contactor, which in turn will be controlled via a low-current relay.

An air duct with a built-in exhaust will be installed under the roof of the greenhouse. It will collect air from different parts of the greenhouse and blow it outside.

And of course, in addition to the air duct, a drive for opening and closing the window will be installed on one of the greenhouse gables. With its help, it will be possible to radically quickly lower the temperature to prevent overheating. In addition to the actuator itself, limit switches are installed on the window frame. They are needed to determine the extreme position.

And now, of course, the control unit itself. This is how it looks from the outside. And this is how it looks without the top cover. Here is the controller board. It is the largest. To the right of it are the universal relay boards. In the lower right corner is the popular motor driver module, which will control the window actuator. To the right of the controller is the temperature and humidity sensor.

The other two sensors measure soil moisture and temperature. Plus, as I said earlier, another sensor is attached right next to the plant to measure the temperature around it.

You can start planting seedlings, and in the meantime I will show you the project settings and automatic operating modes.

There will be only one specific setting, which is when instead of “Soil Heater Temperature” I will measure “Plant Temperature”.

As for the automatic operation modes, there are several of them. It cannot be said that they should be only like this. I am showing my settings at the moment. And you should understand that periodically my wife or I make some changes to them. Therefore, use them only as an example and create your own, more perfect ones!

I also strongly recommend that you watch the tutorial video step number 6 , which explains what automatic modes are and details how to set them up. In this case, it will be much easier for you to understand what I will tell you next.

So, the first mode is called "System". This is a service mode that will not be used independently, as you can see, its tasks can often be found in other modes.

First of all, the controller cooling conditions are set here. Temperature and cooler on time.

Basic notifications are also configured here. Communication, controller temperature, undesirable air temperature, and a separate notification for critical air temperature. The last one is air humidity.

These notifications will be used for the spring mode. For the summer mode, when the greenhouse is already open, a different set of notifications will be used.

The next mode is called Spring. This is probably the most important mode for a greenhouse, because its main task is to ensure the successful growth of crops planted in early spring. Let's look at the tasks for the devices.

I'll start with heating. The main condition for seedling growth is to try to maintain a soil temperature of at least 18 degrees. That's why this target temperature is set here. But the most interesting thing is that instead of the heater temperature, we will simultaneously control the plant temperature.

The minimum is set at the same 18 degrees. What does this mean? This means that even if the soil is still warm and the air begins to cool, the heating will already start to turn on. This makes it possible to soften the sharp drop in air temperature, which, as a rule, cools faster than the soil.

The maximum temperature is set for other reasons. It is needed to limit the operation of the heaters so that they do not damage the seedlings while warming the soil to the temperature we need. Then the heaters will periodically pause and turn off.

Now let's look at Ventilation.

In a greenhouse, excess humidity will be a more frequent occurrence. Due to poor thermal insulation of the walls and temperature differences, moisture will condense on them. Therefore, combating high humidity with an exhaust hood does not make much sense for a living space. The first thing to do is to ensure guaranteed air recirculation so that it does not stagnate, contributing to late blight, and the plants can breathe.

An ideal exhaust hood should work constantly to ensure gradual and uniform air circulation. Unfortunately, the reality is that ventilation will also carry away heat along with the air. When overheated, this is certainly a plus, but in early spring, it is a big minus. Therefore, in cold weather, ventilation in a greenhouse will be a compromise between useful gas exchange with the removal of excess moisture and the unwanted release of expensive and valuable heat.

Combining all these tasks at once will not be as easy as it may seem at first. I came to the decision that the removal of excess moisture from the greenhouse should be done by heating it and as far as possible. And the ventilation should work as long as possible, but long enough not to lower the temperature below a certain level.

As a result, I came up with the following list of tasks:

First task. One sixth of the power. Why one sixth? Because according to this task, the ventilation will work no more than ten minutes per hour, this is one sixth.

Please note that from here on we ignore humidity. We look only at the temperature. If the temperature is over 13 degrees, then turn on the ventilation for five minutes every half hour. At the same time, if during these five minutes the temperature drops below 12 degrees, then this is critically low and then we do without ventilation at all.

Also, an interesting point is that I do not limit the operating time of the hood here. Why this is so - will become clear a little later. And according to the schedule. As you can see, I forcibly excluded night ventilation, when it is especially necessary to conserve heat.

The second task. One third of the power. Will turn on the hood for another ten minutes per hour. That is, in total with the first, it will be two sixths or one third of one hour.

For this task, I have already increased the criteria for turning on and off ventilation by temperature. This ventilation will turn on, or rather will be able to continue working after the first task, but only if the temperature in the greenhouse is high enough.

In addition, I narrowed the time interval a little so that the greenhouse warmed up faster in the morning and lost heat more slowly in the evening.

Third task. Here I immediately add twenty minutes to one hour for ventilation. Together with the first two, this will be two thirds of one hour. The criterion for continuing the ventilation will be an even higher temperature in it. Additionally, the time interval is also narrowed.

And finally the fourth task. For continuous operation of ventilation, an even higher temperature will be required. Similarly, an even narrower time interval.

The very last task is used to turn off the ventilation in any case. It has the lowest priority, meaning it will only work if the first four tasks are not in effect. This task is necessary to be absolutely sure that the ventilation will be turned off at night.

That's all about ventilation. Now it's time to talk about how the window works to ventilate the greenhouse.

As you can see, there are two tasks here. I'll start with the main one, it's called "basic" and works by default 24/7.

The first pair of dependencies is indicated here. At a temperature of 18 degrees and less, the window position should be two percent. That is, practically closed. And the second pair of dependencies at the maximum. When the temperature is already more than twenty-six degrees, the window should be open by ninety-six percent.

We also see that the minimum step for changing the window position is set. Plus, the maximum step for a single-moment change in the window position is also set. What is all this for? Thanks to these settings, you can avoid senseless jerking of the actuator and, accordingly, its premature wear.

But that's not all. A very interesting parameter is the dependence curve. Here is our graph. It has two points according to the given conditions, this is the minimum point and the maximum point. The vertical scale is the window opening percentage, and the horizontal scale is the temperature.

The blue color on the graph shows a linear dependence, which is usually set by default. What is wrong with it? And why did I decide to change it to a curve, which is shown in red?

The thing is that initially everything looks logical: the more the temperature rises, the more the window opens proportionally. However, in practice, it is necessary to take into account the factor that the temperature rise in the greenhouse can occur non-linearly, that is, very sharply.

Yes, theoretically it is possible to lower the temperature range so that the window opens in advance, as early as possible. But is it good? After all, ideally, I need to keep the maximum permissible temperature in the greenhouse as long as possible. That is when the soil will warm up better and more, and then I will need to warm it up less in the evening or at night.

Simply put, opening and closing the greenhouse window in a timely manner will provide significant savings on heating, plus a natural bonus for plants due to a longer warm period of the day.

That is why I formed such a curve, which at the beginning of the temperature increase, begins to gradually open the window, and then the further, the more radically, in order to get ahead of the trend of increasing temperature.

We've sorted out this task. But why do we need the second task? From its name and time of action, it follows that it will work in the evening. The basic task is necessary for opening the greenhouse window primarily in the morning and during the day, and in the evening it must be closed somehow differently.

Why? All for the same reason of economy and efficiency. In the morning and during the day we are allowed to open the greenhouse window earlier to quickly remove the high humidity of the night and reduce the likelihood of overheating, but in the evening we need to do the opposite, shift the compromise in the other direction and warm the greenhouse better, preserving more heat. That is why I set a higher temperature range in this task.

And what I have left for this mode is the watering device. There are no tasks here. Of course, they can be set, but from my experience, they are not needed yet. Because watering at the stage of seedling growth is done manually with fertilizing and careful inspection of the plant.

That's all. Let me remind you that I have analyzed the main spring mode of the greenhouse. Main because it is the most important and responsible. It is this mode that will determine how quickly the harvest can be obtained and at what price. However, of course, there are other modes.

The next one will be the summer one. Let's see it by devices.

Ventilation. There is one condition here - in extreme heat. In summer mode, the window and door of the greenhouse are already ajar all the time. Therefore, gas exchange of plants and humidity control are self-regulating. It remains only to remove excess temperature in case of overheating.

Heating. Will naturally be switched off in any case.

Watering is also disabled for now. Because it is not always needed.

And the window. As you can see, it will be maximally open, with the only condition that the temperature is not less than 18 degrees. In this case, the window drive can close it for some time at night. And even if the door remains open at this time, then still, due to the lack of a draft through the window, the smart greenhouse will be able to exclude accidental hypothermia.

Now an extended summer mode. It is clear that it is completely identical to the previous summer mode. The same tasks for ventilation, heating and windows, but now there are also custom tasks for watering.

Let's look at them. Watering consists of two tasks.

The first one provides a certain minimum of water supply to plants. It works regardless of the humidity and temperature of the soil. It turns on from morning to evening, at the beginning of every second hour with a ten-minute limitation.

The second task is the main watering. Its purpose will be a good watering of the plants in order to moisten the root system as well as possible in depth and width. It also works on schedule. Strictly at ten o'clock in the morning and five o'clock in the evening. It turns on for twenty minutes. Again, it does not depend on the humidity and temperature of the soil.

Yes, I understand that it would be logical to make a task that would water the plants based on humidity or temperature. But from my experience, measured watering has proven more effective. Perhaps in the future I will add a condition for watering based on soil temperature when excessive overheating occurs.

And the last mode is autumn and winter. When the greenhouse is resting. Everything is simple here. Ventilation is off. Heating is off. Watering is off. The window is open.

This concludes my review of my smart greenhouse. I must say that this review was prepared for three years, through research and improvements. If we talk about the results, the smart greenhouse showed itself to be excellent. First of all, it allowed to get an excellent harvest two weeks earlier than a regular greenhouse without automation, which showed worse results due to accidental overheating or overcooling.

In addition, the smart greenhouse has saved our family a lot of time. It has added the ability to leave for a long time in the summer, feeling calm, thanks to remote control.


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