Toilet paper has been tested by a variety of smart bracelets, and there are actually “heart rate”! This is definitely not an accidental probability event!
Here, the smart bracelet is no problem, but the normal tool uses the wrong place, which produces a wonderful effect, which is naturally amazing.
In our general thinking, the smart bracelet can test the heart rate. The first thing that comes to mind is that by counting the number of beats on the wrist, the result is there. The toilet paper obviously has no pulse beat, but has a heart rate, so it is very strange.
In fact, most of the heart rate measurement functions of the bracelet are not carried out in the manner of “counting pulse”, but in an optical manner. After the light from the bracelet is reflected by the skin tissue, the reflection is collected by the sensor. Signal, analyzed waveform obtained.
This method name is called photoplethysmography PPG.
The main principle is to use light to penetrate the skin tissue and then reflect it to the photosensor. At this time, the light will have a certain attenuation under the flow of blood, and then the sensor will collect the light of these different reflections, and then turn it into a digital signal. The heart rate value is output by the algorithm.
Therefore, as long as the reflected light received by the sensor changes, the heart rate can be detected. There is no such thing as living body testing.
Since the wristband is fixed on the wrist, the skin, muscles, and bones do not change greatly in a few tens of seconds of measuring the heart rate, and the blood in the blood vessels is constantly flowing. As the heart beats, the blood flows. It is also rhythmic.
Therefore, the bracelet is illuminated by the LED light, and after being reflected by the skin tissue, the photosensitive sensor receives the light signals that change according to a certain rhythm, converts them into electrical signals, and converts them into digital signals, forming a waveform diagram of the PPG signal like this.
Although the current smart wearable devices have such “bugs”, in fact, this matter is easy to understand in principle, but the results are not in line with common sense, so many people feel incredible. To give a simple example, if you put the thermometer in hot water, the reading will rise to high. The water has temperature but it does not mean that the water has “body temperature”. The same bracelet detects the light reflection instead of really helping you count the heartbeat. Just under a certain range this data can reflect your heartbeat.
The fact that the bracelet can detect the heart rate of the toilet paper does not explain anything. It cannot be said that the technology is not rigorous. It cannot be said that the bracelet is being falsified. All products have a range of use, and the wristband measures the heart rate to be worn on the wrist. It is normal to leave the wrong result in this range. This “error” and the “tea submerged” test in the same year The farce of a large number of diseases is similar, but in fact they all made the same mistake.
It is also not advisable to leave the scope of the function and to talk about the toxicity of throwing away the dose.
In fact, whether it is a watch or a bracelet, when designing, the object is by default. That is to say, under this premise, “measurement accuracy” is the result of discussion.