I use a lot of different temperature and humidity sensors in a smart home, mostly I have sensors from Xiaomi, I have 10 pieces of them, and in principle I bought even more of them, but I gave away some, and of course I really like this sensor, it is very compact, it uses a small CR2032 battery, etc.

the advantage is that the sensor can certainly work from such a battery for a very long time, that is, I now once again begin to gradually run out of batteries in these sensors, one of the first was such a sensor, it stands in the bedroom and it has already worked for more than 400 days and the charge shows 83 percent, that is, I think that it it will work for another 50 days, but it has already started having problems.

It periodically does not send a signal to the smart home system.

it tracks me so that if the signal does not pass, then I can always see on the dashboard that if there was no signal for more than an hour, then it is highlighted with a certain sign, if there was no signal for more than a day, then another sign is indicated there, and this way I can always understand that something has stopped there even this figure can no longer be trusted, because in scenarios for example, I don't always process it so that the value there is no older than such and such a time, of course it is better to do this, otherwise it may turn out that the value there is, I don't know, last year's and in fact something will be included based on this value that you won't need to run it at all.

There are the same Aqara sensors, they just have an additional option there, they measure pressure, but by and large, pressure in a smart home doesn't really need to be measured, because you can just take one sensor from an external site, or it's enough to determine the current pressure in general.

that is, it makes no sense to put such a sensor in each room, and the Xiaomi sensor and the Aqara sensor, in principle, send the value once an hour, somewhere every 55 minutes, this is just convenient for accumulating statistics so that it can then be built up without problems, at least in hourly breakdown, but either sends the value if it has changed by more than half a degree and humidity if it has changed by more than five percent, this is also not always convenient, in principle, this is like a restriction for him, that is, if he sent more often, it would also not be very good, but if he sends with such frequency, then sometimes for example when he has I have on the basis of this sensor works some kind of thermostat, let's say it includes a radiator, an additional electric heater, through a smart outlet, or a relay, that is, of course, I can't actually track that the temperature there has increased and now I need to turn it off in a timely manner, and no PID controller is needed in order to somehow set the temperature more smoothly, that is, it will not allow me to do this, I just actually wait until the next measured signal arrives, the measured temperature and based on I just already make a decision, if it is more than a certain threshold, then I turn off the radiator, if less, then I continue to warm it, that is, of course, this is not a very convenient restriction.

But I measure the temperature in the rooms more for the purpose of monitoring, that is, to understand where it is very cool, somewhere it is not very cool, maybe somewhere the window was forgotten to close and this also sometimes becomes visible, for example, in winter I see that there is a very sharp drop in temperature in some room, then I I understand that they just forgot to close the window, then you need to close it, for example, when they were airing, well, or something may have stopped working there, for example, if it's very cold I use additional electric heaters, I use them in the off-season, then if I see that the room is already cool, then maybe it's just for some reason for this reason, it does not work and there may be a wi-fi outlet from Tuya, for example, the Internet connection is lost, and it does not work, so I can also check it through the temperature sensor, and in general, understand what temperature is comfortable, what temperature is not very comfortable, maybe somewhere on the contrary, it was like this that I just have the opposite outlet left in the on state and still on the radiator there can generally disconnect, connect directly to the outlet, set the desired mode and there it will heat up, I had it so that the room was heated up to 30 degrees, and then I saw from this sensor that there was an abnormal temperature in general, and I went to investigate, that is, this can also happen.

Well, in general, it is useful to track, for example, I have such a sensor on my balcony, it tracks the temperature, and I understand that if I want to store some products there, for example, use it as an additional refrigerator in winter, then of course it is important for me that everything does not freeze there and it does not fall below zero, then I thus see what change there was and I also track it and based on this I make different scenarios, mainly these are of course related to heating, there is no problem with cooling, but in theory if there is an air conditioner, then you can also track the sensor when to turn on the air conditioner, when to turn off the cgo, of course you can simply turn on the cooling mode, or maintain the temperature, well, first of all, it will always be on, and sometimes, for example, if people left the house, then there is no point in cooling even if it became very hot, then of course you still need to do more complex scenarios, that if people all left, then you can not cool it, if people have come or are going to come, then understand accordingly by time, or in some other way that it needs to be turned on and the temperature should be maintained.

It may also be that it turns out that even in summer it is quite cool and it may be necessary to warm up the room on the contrary, and not cool it, and if the air conditioner does not know how to turn on itself in heating mode, or in principle it does not have such a mode, then it will also need to be handled more correctly.

But in general, even if the window is open there, then in general it may not be necessary to turn on the air conditioner in any case,as well as heating.

Well, I certainly use humidity parameters mainly for monitoring, I don't really bother with installing humidifiers in rooms, filling them, washing them, this is too difficult and actually doesn't make any sense, because in winter the humidity is still very low, it is due to both constant heating and the fact that air is drawn from the street and it's actually dry there, it's also all useless, and by and large I don't have humidifiers and I don't use them at all.

I have one touch humidifier it is inconvenient to use it because I can't turn it on or off through a smart outlet, well, I can turn it off of course because you can just turn off the power, but this is also not very convenient and it quickly runs out of water there,and therefore there is no point in this.

It is already necessary to make a full-fledged humidification system special, so that everything is clean, clean water and the whole system works correctly, then you can probably maintain it, but it is also important that after all, I have a CO2 meter, and if you constantly ventilate or constantly open the windows, then in general it will turn out so that all the humidity is it will quickly disappear and there is no point in it at all.

The main application, of course, is that I have such a sensor in the bathroom and it turns on the fan if the humidity is very high, that is, you can manually turn it on of course, but if you suddenly did not turn it on, it will turn on, also if you forgot to turn off the fan manually, then it will also track accordingly that the humidity it is necessary to keep the fan there all the time in the on mode, and it will turn it off after a while.

And it is also made that if everyone just left and the humidity is there, and the light is turned off, then I just automatically turn off the fan after 30 minutes, because in fact he has all attempts to lower the humidity, they end in nothing, it is necessary to ventilate it for half a day so that he at least pulled something, that is, even a good a powerful fan will still not be able to do this well, it will be easier to open the door itself over time, or open the door, the simplest of course, and ventilate it, and then the humidity will come out and others will also get into the rooms, which is also convenient, and if something is drying there, or everything is wet, let's say in the bathroom, that is, physically, it will just evaporate for a very long time, and constantly, and this can be ventilated almost indefinitely.

The sensor itself works quite accurately, it shows the temperature, well, like all the others, it's absolutely true, they all show it, because it's too simple and any cheapest sensor it will also show there up to hundredths of the actual correct temperature, but of course such accuracy is no longer needed, with humidity of course, everyone has a different temperature.In different ways, even two identical sensors from Xiaomi can show different humidity, but plus or minus it is certainly understandable, still if it is high, then it is high on all sensors, and if it is low, then it is low.

They just have different values, and there you can either calibrate the sensor, or just specify other ranges in the script, for example, I have one sensor from Xiaomi that shows 65 percent humidity, then a homemade sensor on Arduino that works, it shows 85 percent there, well, in general, it's clear that both are true in this case, you need to turn it on, because for Xiaomi this is essentially the limit value, even there, in principle, it never rose higher, maybe it just does not show correctly, and where it has increased, you can just turn on the fan or inform it somehow so that the door is opened or something else, if it has gone down there up to a certain threshold, for example, set 45 or 50, in this case it is simply either turned off or also informed, that is, in principle, such accuracy is sufficient in any case for such a scenario.

I connect them via zigbee2mqtt, in principle, all their parameters are normally added to the Home Assistant smart home system, and also in principle, in OpenHAB, they appear in the zigbee2mqtt application itself, you can also view these parameters via the web page, and in principle everything is shown normally, well, plus except for temperature and humidity, it also shows the batteries, this is also convenient, that is, you can track that there is some voltage, it depends a little on the overall temperature, that is, if the sensor is hot, then it will show more battery charge, if it has cooled down, then less, it will also show as a percentage, that is, there is one hundred percent the battery charge, or less, and also the signal strength, if the signal is not very good, then of course the battery will sit down faster, because first of all it constantly measures the current temperature, there is somewhere a trigger in a second, if you blow on it or somehow change the temperature sharply, it it reacts very quickly, so the signal is of course very weak, and if there is no zigbee router to use, it will sit down much faster, so of course it is important that there is some kind of device near it, which acts as a router and helps it communicate with the smart home system.

Automation in a smart home should be useful and create additional comfort, but sometimes everything goes wrong… The reasons for this, and how to configure everything, see on my channel.