Saturday, September 11, 2021

Smart watch (2)

I wrote at the beginning of the week about my new Xiaomi Band 5 smart watch. Over the past few days I've been playing with the watch and discovering new functionalities. At the same time, I have become less and less enamoured of the watch, primarily because of the user interface and secondarily because of the inaccuracies in the data.

User interface: I appreciate the difficulty of trying to cram no small number of options onto a small screen when the only control functions are pressing the bottom of the watch, swiping up and swiping down. Of course, it would have helped had the minimal user manual include a map of the functions and how to access each one. I will return to the user interface later on.

Inaccuracies in the data: I already noticed the difference in the number of steps being counted by the watch as opposed to the steps counted by my phone. After I discovered the 'walk exercise' function on the phone, I decided to test this on a long walk; I forgot to start MapMyWalk at the beginning of the walk so I had no comparison at the end. The smart watch said that I walked 3.55 km when I'm sure that I walked more. The second evening I started both the watch and phone at the same time: they agreed on the duration of the walk (45.1 minutes) but on nothing else. MapMyWalk says that I walked 4.12 km burning 258 calories (no step count) whereas the watch says that I walked 2.93 km in 5855 steps, burning 372 calories. Big differences! I tried a third night; I started MapMyWalk about 200 m from my home and recorded 3.98 km whereas the watch says 3.16 km.

From a discussion of Reddit: Miband doesn't have GPS but while you're walking, it counts your steps, with that information it calculates an approximate distance. 

I thought that the watch somehow utilises the GPS in the phone to which it is paired via Bluetooth, but apparently not. Counting by steps is not a good method of calculating distance as the length of each step is not constant.

After having given up on the walking function of the smart watch, I was interested to see how the swimming function would work. I took my reading glasses with me to the pool yesterday so that I could see the menu options on the watch, but I couldn't see a thing because of the light. I guessed how to start the swimming function but guessed wrongly (I'm not sure what I did choose). This morning I started the swimming function before I left home so at least I could see what I was doing. I was asked the length of the pool and then the watch started measuring. When I got home, I looked at the watch again, trying to figure out what it had measured and how to stop it.

In trying to stop the swimming function, I noticed that it had at the bottom of the screen a small icon with an arrow pointing to the top of the screen where another icon waited. Sweeping the surface of the watch caused the icons to switch places; the arrow changed direction. When I saw this, I realised how the watch was measuring: one is supposed to sweep at the end of each length, and as the watch knows the length of the pool (because it was told at the beginning), it can calculate how many seconds it took to swim the length and from that how much energy had been expended. I can just see myself stopping after every length to change direction of the watch (NOT!).

Then I tried to stop the swimming function. This was exceedingly difficult: every time that I swiped, the direction of the arrow would change but there seemed to be no way of actually stopping the measurement. Eventually I saw that a red button would appear briefly; somehow I managed to get this button to appear for more than a second and then pressed on it, finally managing to stop the watch. Terrible user interface design.

So I'm not going to use the watch to count steps and I'm not going to use it to measure long walks and I'm certainly not going to use it for swimming. Am I going to use it at all? The sleep measurements seem to have some amount of accuracy, although one day it showed me sleeping at 8 am when I had got up at 5:30 am. I can see the length of sleep along with how much deep sleep and how much REM sleep I got. I find it strange that the first night I had 8 minutes deep sleep and no REM sleep, whereas later on I have over an hour deep sleep and over two hours REM sleep. In other words, I have my doubts about this data too. The only thing that should be accurate is pulse measurement and even that does not agree with my personal sphygmomanometer.

So it looks very much as if I am going to abandon the smart watch.

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