introduction

I am a research and development engineer, and now I am a part-time researcher on SCM, so my evaluation is different from the general evaluation. The general evaluation focuses on the appearance, and lists various functions for everyone, just like the manufacturer's advertising. I generally scan through such evaluation, and feel that there is nothing interesting. In this evaluation, I complied with my promise when I applied to disassemble Yunmai Haoqing MINI to see what kind of high technology was in his stomach. At the same time, we will introduce some principles of electronic scales.

Unpacking

My evaluation is mainly for follow-up functions. In order to take into account the students who have not seen the unpacking, here is a simple unpacking. My machine is sent for testing by Lei Feng.com, so the packaging has been opened. It doesn't matter whether the original package is unpacked. However, due to the seriousness of Lei Feng.com staff, the packaging is still very good, with a layer of foam on the outside of the box. The package I received was complete and undamaged.

The box used for packaging is a corrugated box, which is not as hard as the Xiaomi mobile phone box. However, considering the manufacturer's cost, this box is good enough to provide necessary protection for the product. From the figure below, we can see that the key position of the product is double-layer protection.

After opening, the following parts are displayed. Since the Apple packaging mode appeared, now all product instructions are packaged with a paper shell.

appearance

There are four electrodes on the front of Yunmai Haoqing MINI. These four electrodes are rounded like four legs of a scale, which makes me think the back of the scale is superior to me when I unpack at the beginning. I hope the manufacturer can change the position or shape next time. Don't let users always think that it is inverted.

Yunmai Haoqing MINI has a refined appearance. The upper panel is fixed by screws, and the four sides are fixed by locks. The naked eye can't see the gaps around, which indicates that Yunmai has really made a lot of effort on the grinding tools. A few days ago, Yunmai's entrepreneurship article mentioned that the mold has been modified many times, which indicates that a lot of effort has been made here. But when I squeeze around the edge, I feel the front end and left side creak.

The back of Yunqing MINI is composed of four exquisite black feet, which are where the sensors for electronic weighing are located. Therefore, the quality of the four feet also determines the accuracy of the weight, which is described in detail in the disassembly section below. It can be seen from the following figure that the legs and feet are independent of the scale, and here the legs and feet are in direct contact with the sensor.

The middle part is a box for batteries, where four No. 7 batteries are placed. The battery box cover can be easily opened, and the damping is just right. The shell is very good, but the interior feels like a new level. In particular, the electrode piece is different from the ordinary battery box. When the battery is added, the spring will be inclined.

Disassembly

In order to let you see the internal workmanship of Yunqing MINI, don't be confused by the exquisite appearance. Here is a demonstration of disassembly. At the beginning of disassembly, only 6 screws were disassembled. It was found that the four corners were difficult to disassemble. Later, it was found that there was a plastic gasket in the four feet. When the gasket was removed, there were four screws below. So if you want to disassemble, you can only separate the upper and lower shells by removing a total of 10 screws. After disassembly, you can see the following parts.

The right part of the above figure is the upper shell. It can be seen from the figure that there is a black frame. The black frame is a steel plate structure, which is heavy in the hand. The steel plate structure transfers all the forces to the four leg positions, because there are sensors at this position. Is to measure the force. At the same time, it also shows that this small scale can withstand 300 kg. The left part is the main board.

This is a digital display tube. The back is a data processing motherboard, but there are still traces of welding from the front welding line. This detail was not done well. The following figure can be seen after turning the back of the motherboard

First of all, we can see that this motherboard is designed by Yunmai. It is black as a whole, which is very high-end. The largest chip in the middle is the LED display driver chip, whose model is TM1628. This chip is made in China. At present, this small chip can be made in China. The Bluetooth chip on the left is used for data transmission. The model is CC2541, which is produced by Texas Instruments. I tried to grab data here, but failed.

This sensor is used to measure the weight. It changes the resistance value mainly by pressing the deformation sensor on the leg and foot, and obtains the total amount information through the group value.

This contact is at the body fat detection contact, through which the current data is transmitted to the mainboard for processing. It may be the manufacturer's secret how to process data from one line into multiple data in APP.

Disassembly difficulty: simple

It took me about 15 minutes to disassemble the mini. The main problem was that I didn't find a washer in the leg to cover a screw. When I didn't remove the screw, it didn't separate. Later, I found that the plastic gasket could be removed and pasted with double-sided adhesive tape. However, the pasting is not very good. There are exposed glue or folds. The others can be disassembled with a crowbar. However, it is recommended that you do not need to disassemble it, because it may make the edges uneven, which may lead to bad looks. The author's this has been damaged. Of course, it is OK to look at it from a distance.

APP experience

Now let's talk about this app. The graphical interface is simple and looks good. Because a lot of parameters appear at once, I feel that this scale is still very high-end. At least that's what my colleague said (note: this colleague is Mifen and has multiple Xiaomi devices). He said that it is more high-end than Xiaomi's software. There may be some compliments, but with so many data, I still feel that it is more powerful.

The software registration interface does not mention that you can directly register or directly use the WeChat account to log in. In order to make it convenient, the author directly uses WeChat to log in. After logging in, the main interface is as follows. The first page is about weight, the second page is about interaction, and the third page is about settings.

First, let's talk about the first page. There is weight displayed, and the weight value in the big circle in the middle is synchronously displayed with the scale, that is, what is the value at the same time when weighing, and what is displayed on your mobile phone is also the same value. So this product has a disadvantage: after disconnecting the mobile phone, the data measured by the scale cannot be uploaded after the mobile phone is reconnected, that is, there is no data processing function such as storage on the main board of Haoqing MINI terminal. It just transmits the original data to the mobile phone and uses the software to calculate the displayed health data. (The above is a personal analysis, not a manufacturer's description)

Let's talk about the second page. The second page is community interaction, that is, clocking. However, it shows that beautiful women and handsome men are very attractive. You can look at them when you are relaxing, but the author will not show them. They have a big stomach.

Finally, let's talk about the third page. This page has functions such as display unit setting and weight weighing time reminding. They are common functions, nothing special. (As I said earlier, the device side has no storage function, but this place has the function of storing display unit system. It seems that it has storage function, but when disassembling, a small chip is too small, and the words on it are really invisible to the author).

Well, look at the first one in the above figure. Since this is a scale for measuring body fat, it needs a small current to pass through. If you wear socks, you will be prompted in the above figure, which indicates that the electrode is not a device, at least it is still powered on. Ha ha. Now let's analyze it in detail. If you test normally, there will be a physical examination report in the middle figure. If you click the curve function on the home page, your recent weight change will appear. Note that the weight here shows your last measured weight of the day, and the figure above shows the data of the author's test for 7 days (Note: the data here is basically that the weight before going to bed at night only wears sleeping clothes, and will change if you go to the toilet conveniently.) You can find that there is a small mountain peak where the weight of other people fluctuates within a range due to overeating at night. See the specific data in the following figure (I wanted to list a table, but later I wanted to take a screenshot directly to illustrate the fact, here I deleted the duplicate data, and editing can only delete the function). When I got up in the morning, I weighed my weight immediately, and wore the same clothes as when I weighed at night.

The two weight changes in the morning of the 25th were the changes before and after going to the toilet. It seems that there are many convenient quantities. Hey hey, can I say for sure? The following details the accuracy of the scale.

The weight difference between the morning of the 25th and the morning of the 25th is 1.0 jin. Note: Why didn't you go to the toilet at night?

The difference between the morning of the 24th and the evening of the 23rd is 0.6kg

The difference between the evening of the 22nd and the morning of the 23rd is 0.9kg

According to Baidu search, there should be weight difference sooner or later, but the analysis says there is excretion, but I don't have it here.

I'll list them here for you to make a decision.

Let's talk about the resolution of the measurement. Although the smallest unit is 0.1 kg, there is no change between holding my mobile phone MX5 (149g=0.3 kg) and not holding it on the scale. At the same time, the author found that there will be a change in the measured value when the mobile phone is taken or not, and both will change back to the previous value. Although there is a jump value, I wonder whether the manufacturer has made special treatment in this place, so that consumers feel that the weight measured by the scale is stable. At the same time, if you take an object of 2 jin (the author here found an unopened noodle), the calculated difference is 0.8 jin (150.5 jin when holding it, 149.7 jin when not holding it). It seems that the error is relatively large.

Let's talk about many additional functions

The official propaganda said that "BIA bioelectricity measurement method accurately measures body weight, BMI (body mass index), fat, muscle, bone mass, water, metabolic rate, body age, visceral fat, protein and other body composition data, and analyzes and records them." In fact, according to the weight, there are some calculation formulas that can calculate some values, such as

① =Weight (kg) ÷ (height × height) (m)

② Body fat rate: 1.2 × BMI+0.23 × age - 5.4-10.8 × sex (1 for male, 0 for female)

Below is an excerpt from Baidu Encyclopedia

Bio-impedance analysis, It is called BIA for short. Traditionally, measurement The current standard is based on DEXA measurement, but the time and cost are quite uneconomical, so a more convenient bioelectricity measurement method has emerged in recent years. Very accurate measurement values can be obtained in a very short time, which is suitable for use in families and doctors in outpatient clinics.

The main principle of BIA measurement method is to simply divide the body into conductive body fluid, muscle, etc., and non-conductive fat tissue. When measuring, the electrode piece sends a very small current through the body. If the fat ratio is high, the measured biological resistance is large, and vice versa. BIA is to measure the body fat ratio through this machine.

So not all the data officially displayed are measured, because how can there be so much data on just one electrode? So we'd better ha ha.

summary

advantage:

• The appearance of the product is pretty good. It seems that a lot of effort has been put into the shell abrasives. It's worth 79 yuan.

• The display screen shows the effect bar.

• The APP interface design is simple.

• Black is a high-end motherboard.

• There is a relatively solid steel structure frame inside.
  

Disadvantages:

• After disassembly, the internal mainboard is not clean enough.

• The host cannot store the weight data, and the weight can only be saved after connection.

• The resolution of body weight measurement is not high. One kilogram is indistinguishable. It may be an algorithm problem. Because there are changes in the fluctuation value, but the final display is not accurate.