Heartbeat detection in a Fitness Watch
Hey friends, Happy Wednesday!
Answer to the question I posed last week
Last week, I asked why air travels faster above a wing than below a wing. Here is an explanation, I have set the URL of the YouTube video to start at the exact time. Watch for 1.5 minutes from HERE
Blog post - How is a heartbeat detected?
While writing the blog post for the heart rate measuring algorithm in a fitness watch, I realized that detecting a heartbeat needed a blog post of its own and is quite interesting. So here we go…
My blog post S1E4 on how a heartbeat is detected is out! Happy learning!
Blog post link on how a Heartbeat is Detected
Actually there are no prerequisites to understand the blog post. But I thought I’ll touch upon the basics of Photodiodes used in a fitness watch. So feel free to skip the next section if you’re familiar with it. I aim to write my newsletter issues in a way one can follow them while traveling on a bus, having a coffee, waiting for your food, etc. Let’s jump in!
What is a Photodiode?
Photodiodes are light-based sensors. When this semiconductor-based sensor is not exposed to light, there is almost no current that is flowing. Once it gets exposed, the temperature increases and the electron movement causes current. Also, the intensity of light is directly proportional to the current that is generated.
They are quick and have high operation speed, long life span, don’t use high voltage, have low weight, are extremely responsive to light, less noise, and are mechanically rugged. On the contrary, they have less sensitivity, small active area, and solely depend on temperature which could be a disadvantage.
They are used in smoke detectors, solar panels, street lights, manufacturing plants, fitness watches, X-ray detection, headlight dimmer, bar code scanners, position sensors, and encoders.
Question of the week
What are other ways in which a heartbeat is detected traditionally, aside from how a fitness watch detects it? Share your thoughts by replying to this email, and we can have a discussion. I’ll answer this in next week’s issue. Thanks to everyone replying to my newsletter issues, I'm learning a lot from you as well.
Upcoming Blog Post
I’m writing about the recently patented Heart rate measuring algorithm by Fitbit in 2022 for the next episode S1E5. Also, let me know if you’d like to read about a specific gadget/device.
Have a nice rest of the week, and take care!
Until next Wednesday,
Chendur
