I tried several times to return to the topic of using different types of smart scales in a smart home, it was possible, of course, to buy some scales and try to integrate them, for example, it can be small scales that are used for cooking, for example, to measure food, the weight of food, or it is large scales for measuring body weight. I also considered different options, how it can be used in the form of homemade devices, I even bought a sensor called a tensor, sensors that measure weight, well, more precisely, they measure the change in resistance depending on the weight that acts on them, there are different sensors, there are for a small weight, it can be in the form of such a rectangle, or it can be a separate, small sensor that is placed directly under the foot of the scale, and these are different measurement methods.

In fact, in order to measure these slightest changes, of course, a special chip must be used here, which allows you to determine what value these scales show, this sensor shows, and then, of course, calibration is done there in order to understand that there is a change in resistance by so much, then this is such-that's the weight. There was an idea to use such sensors in several different scenarios, that is, initially I considered a way to determine the presence of water in the kettle, because I wanted to automate the operation of the kettle, and, of course, the easiest way is to determine if there is water in it, it's just to weigh it, but there were no such compact devices that is, it would still be such a large enough device, which, firstly, needs this weight sensor itself, and also needs some kind of microcontroller that will process it and send it to the smart home system, you also need to bring up the power supply.

That is, in principle, a rather complicated topic, and you also need to make sure that the kettle still stands on this sensor, on the scales, and also does not fill this sensor with water, in the case when, for example, the kettle was filled there, there may be a lot of water poured, or it just is not very dry it turned out not to fill in all the contacts either. There were different ideas, there are some options, such as measuring the weight of, for example, a gas cylinder, if, for example, some kind of separate cylinder is used, there, for example, for barbecue or some other applications, for a gas stove, then you can simply put such scales under this cylinder, and then you will see how much gas is left there and determine by weight when it needs to be changed and warn you in a timely manner, make yourself some kind of reminder or make some kind of signal in a smart home so that it is visible. I had an old scale, which was pretty good in a metal case, and then they were stupid of course. They used small CR2032 batteries, 2 pieces, and very often the batteries were discharged and, of course, I wanted to find a more different solution. At first I tried to make a separate external power supply for these scales, but then over time some of their contacts also broke down, and they did not turn on every time, and, in general, I had to disassemble and look at them, and just there it was very interesting that 4 weight sensors were used inside, this the classic scheme, in principle, it is available, you can buy it in Chinese stores, I even ordered it at one time, but, of course, for some reason they did not send it to me, as a result I did not try to use it.

But there was an idea to take these scales using those sensors that were already installed there, just change the chip, add a microcontroller there, for example esp8266 and just make sure that these scales immediately transmit information to the smart home system, but then I just already saw on the Internet that Xiaomi scales had a big discount, they that- then it cost me 800 rubles in total, this is Body Scale 2 and they have already integrated too, well, more precisely, they supported the bluetooth exchange format, it was possible to install a program on the phone and, accordingly, see all the values in the program initially I thought, that you can somehow transfer this information from the program, for example, connect it to the Home Assistant, or rather, connect them first to Mi Home, and then transfer either Home Assistant or another system, but it turned out that they do not connect to MiHome, use a third-party application, and then this application became a different manufacturer altogether, and, in general, these scales could not be integrated in reality through the application, but since the bluetooth format is used there, BLE, there were enthusiasts who nevertheless disassembled this protocol, found a way to connect to these scales, and in principle, it was quite good to take the value from these scales, that is, in fact, 2 values are taken, these are weight and impedance.

And then you found a formula there that can be used to calculate all the other parameters of the body, this formula is not very accurate, it is some kind of approximate, and, of course, it differs greatly in values from those specified in the application, after all, the application, it is based on some big data, and it's not just that the simplest formula is used there, which is already 20-30 years old, these are more complex calculations, some statistics are taken into account in the whole world, and, of course, it will probably be very difficult to repeat it manually, I've been trying to track and compare values for some time, I thought I would either do some kind of mapping of these values so that, in principle, it would be possible to compare the parameters and show them close to those made by the calculation manufacturer himself, but in the end, in principle, it turned out to be not so important, the values are, of course, approximate, but in principle it is relatively possible to understand that my health is improving there now, or my health is deteriorating, or some parameter is changing there somehow, and try to influence it already.

Well, in the end, I connected via ESP32, because it has Bluetooth, Bluetooth support, and it can work with BLE and Wi-Fi at the same time, so it transmits parameters to the smart home system via Wi-Fi, and I save them.

And, of course, now these scales, they are in my smart home system, and information from everyone who is weighed on these scales, it is saved, and it is very convenient, it can then be used somehow, and I save almost all the parameters, plus even the calculated ones, so that you can also have some to build graphs, and every time so that you don't have to recalculate.

There was some difficulty with these scales, since different people are weighed on the scales, then, of course, many have the same weight, very similar, and I had to study how to determine who exactly is being weighed, and in order to record the parameters for the right person, I eventually found a way when I just based on the impedance and weights, using pre-configured parameters, age, weight and height are set there, and then, accordingly, everything else is determined based on these parameters, all other human parameters and biological age are determined, and based on this biological age, it is already possible to determine who exactly these parameters are more suitable for, and thus identify a person and already save this data in 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.