• Subir Biswas

Why smart watch use green light for pulse sensing

Updated: Nov 14

We are wearing smartwatches for the last 10 years. But do you ever want to know why there how it is sensing the pulse and why a green light is using for the sensing? interesting..!! Here are the details.

Reason 1:

Blood is red because it reflects red light and absorbs green light. Smartwatch uses green LED lights paired with light‑sensitive photodiodes to detect the amount of blood flowing through your wrist at any given moment. When your heart beats, the blood flow in your wrist, and the green light absorption - is greater. Between beats, it's less. By flashing its LED lights hundreds of times per second (vary from manufacturer to manufacturer), the smartwatch can calculate the number of times the heart beats each minute - your heart rate.


Reason 2:

And additionally, the green light is less susceptible to ambient light. This means this green light will not affect much in ambient light compared to others and in this way, this light can give more accurate results while performing the puls sense activity.


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#smartwatch #pulsesensor

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