Working of Heart Rate Monitor explained | Today I learned

Working of heart rate monitor explained | Today I learned

Working of a heart rate monitor explained | Today I learned

Curious minds are the best minds. People who question everything are my favourite kind of people. Let us talk about curiosity questions behind heart rate monitor.

Owning a gadget  becomes more meaningful when you know each and everything about it. How do the elements work and what they do exactly on the device.

We all know about heart rate monitors on our smart devices. Be it phones, fitness bands, fitness watches, smart watches, heart rate monitor devices.

Here we won’t be talking abut professional heart rate monitors used by doctors but the everyday use heart rate monitors that give more meaning and stats to our workouts, jogs, runs, step counting etc.

Working of heart rate monitor explained | Today I learned

Components of a heart rate monitor


     1.Light Sensor

They can be of many types. Depends on the company. The type here is not necessary, almost all have similar principles.

     2.Light Source

The light source is typically a LED. Most companies use Green colour LED. Why the green colour you ask? Well, there is an explanation for that as well. Read on.

Principle of the heart rate monitor

It works on three principles of different domains. The machine principle, the body principle and the light principle.

  • The machine principle :

The heart rate monitor works on the principle of absorption and reflection of light. The sensor detects the amount of light reflected and based on that information we get to know our heart rate.

  • The body principle :

Our veins have capillaries which contain blood. The red colour of the blood is because they absorb all other colours and reflect red. This information is vital when I explain the working of the heart rate monitor.

  • The light principle :

Light has property to get reflected or absorbed. This property helps us see the colour we want to see. All colours are absorbed by black and similarly white reflects all the colours.

Working of the heart rate monitor

Working of heart rate monitor explained | Today I learnedWhat does the light source and the sensor do?

The light source sends green light through our skin into the blood. The blood being red absorbs the green light thrown at it. Photodetector sensor senses this absorption.

What does the sensor actually sense?

More the absorption of light lesser is the light reflected and vice versa. This reflection of less or more light is detected by the photodetector. The light reflected from the blood capillaries.

How does this absorption measure our heart rate?

Absorption is directly proportional to the blood present/blood density. More the blood more is the absorption i.e heart rate is higher. Density of blood varies and so does light absorption by the capillaries.

Less absorption means less blood capillaries to absorb light i.e heart rate is lower.

What happens if our heart rate decreases or increases?

When the heart rate monitor shows 73 it that means blood is being pumped into our veins at a rate of 73.  More blood being pumped will show higher heart rate. More blood means more capillaries and more capillaries means more absorption of the light.

That’s it. Optical heart rate monitors are that simple. They just use simple principle of light and voila!

Where can you find optical heart rate monitors?

Working of heart rate monitor explained | Today I learned

  • ECG or EKG machines used by hospitals detect most accurate heart rate. That method is too bulky and far from practical.
  • Professional athletes use strap on bands that have same electrodes found in ECG whereas normal consumer feels awkward and not practical with this method too.
  • Smart watches, fitness bands and smart phones use optical heart rate monitors thereby a close to accurate heart rate is available at no extra baggage or cost.

All about the Fitbit Versa | One week Review


Main drawbacks :

Inaccuracy constitutes the skin texture, less amount of light reflected, processing.

Skin texture

Tattoos or dark skin or others absorb a lot of light resulting in poor results.


Bones, muscles also reflect or absorb light which makes the processing difficult as not all light is from or to blood.

Reflected light

The light reflected to the sensor is very less. This poses a problem too.


Now you can tell this to your friends and family. You know what you are wearing and you now know how it works. That is the kind of confidence we all dream of don’t we?

Fitness X Tech

Looking for fitness bands. Get to know which are best for you



Mi MIX 3 | Upcoming Smartphones


Mi MIX 3 | Important Specification


Not a tech geek are you? Well neither am

I. Here is everything you need to know about the upcoming Art Mi MIX 3 , as they are calling it from Xiaomi.


  • The Mi MIX 3 is all set to release on 25th October 2018 here in India. Mi on their official twitter account have flamboyantly marked it as ART X TECHNOLOGY. No doubt that from the leaked Images surfacing on the Internet this is indeed a different and beautiful phone.

  • It is not even close to the clone smartphones available in the market right now. Every phones just looks like the one right next to it. Mi MIX 3 has a dual front facing camera for better face recognition

  • The phone is expected to be priced near about 35000. It will give intense competition to the newly released One plus flagship, The One plus 6T.


  • Mi MIX 3 has a dual front camera (24 MP) as visible in the photos. This improves the face recognition. The phone also boasts of a Selfie-Light. In the market after this their might not be any that can give competition in terms of selfies.


  • Brace yourself for this one. Mi MIX 3 comes with a whooping RAM of 10 GB. You don’t need to re-read that. It is indeed 10 GB. So all your problems of multitasking are now solved. Play PUBG and ASPHALT simultaneously if you wish to and it will run smoothly as ever.


  • Mi MIX 3 is expected to come with a glass back so wireless charging should be enabled. The glass back looks classy and gives the premium look that you expect to get in 35K smartphone.
  • According to a different Weibo leakster, the Mi MIX 3 won’t be coming with an in-display fingerprint reader but with a rear-mounted one instead


  • According to a Video released by Mi on their official twitter account. The screen of the Mi MIX 3 is a slider. You slide it down to make way for the camera which then recognises the face in milliseconds and unlocks the phone.


  • Other Specs Being,  Xiaomi Mi MIX 3 mobile features a 6.4″ (16.26 cm) display with a screen resolution of 1440 x 2560 pixels and runs on Android v8.0 (Oreo) operating system. The device is powered by Octa core (2.8 GHz, Quad core, Kryo 385 + 1.8 GHz, Quad core, Kryo 385) processor paired with 6 GB of RAM. As far as the battery is concerned it has 4000 mAh.


  • Rear camera in this mobile has a 16 MP + 13 MP camera Exmor-RS CMOS Sensor supporting a resolution of 4616 x 3464 Pixels and the front snapper is powered by a Exmor-RS CMOS Sensor. Other sensors include Light sensor, Proximity sensor, Accelerometer, Barometer, Compass, Gyroscope.


  • No, haven’t forgotten about the fingerprint sensor. It does have one.


  • Maximum memory is 256 GB and not expandable.

These are some of the main specs bulleted for all of you. Hope you now more about the Mi MIX 3. It looks so good that I can’t wait to get my hands on.

For pictures check out Mi Official Twitter Account

For more articles like these Check out our Fit-Tech Section



All about the Fitbit Versa | One week Review

smart watch

All you need to know about the Fitbit Versa | One week Review

This is a comprehensive review of the Fitness smart watch Versa Released on 13th May in India at a price of 19,999 Rupees.

Categories :


2. Hands on Fitness Experience


4. Water Performance

5. Sleep Tracking

6. Women Health

7. Music

8. Miscellaneous

  1. Aesthetics

The watch looks classy on any hand. It is a unisex watch and looks great on both the sexes. A very soothing design that does not shout BIG ELECTRONIC GADGET ON MY WRIST. Most importantly the quality of the material gives it a premium feel and look. Nowhere near to cheap plastic that just feels wrong any day. Definitely a go to if you want a smart watch with them looks.

  • Very chic with formals.
  • Works like a sports watch but certainly doesn’t feel like one.

2. Hands on Fitness Experience

I wore it 24×7. Did not even take it off once. With Complete use with notification the battery ran for 3 full days and on the 4th day there was still 17% of it left when I put it up for charging because I am frenzy like that. It sits on your wrist very comfortably. Never too bulky or in the way of your normal chores. It becomes a part of you.

Full use

I tried using every mode available. Be it Running, Workout, Swimming, treadmill and more. Used the relax app. Tried using Uber. Deezer, unfortunately does not work in my country which is a bummer. All in all it is a good watch but mine had a problem where it just showed my heart rate to be too damn high. Fitbit really needs to send an update to fix this issue. This is not exclusive to me but I found forums related to this. FITBIT.

Gym sessions

Daily Gym sessions. Weight training. The heart rate seems pretty okay though I was told by my trainer that it might be showing too much. After checking on the internet my Max came out to be 199 and the fitbit showed 192 sometimes which seemed a little on the higher side. This is something I did not expect to be extremely accurate it is reasonably good.


– Works fine when showering. Just the touch becomes a little hard.

Accurate Heart rate

– Seems just fine. Not too accurate but just fine. If you are into sports and tracking everybit. I advice going against buying it. Not for professionals. It is for people who go to the gym, sometimes go for a run and minor activites. Nothing major like Mountain climbing, daily hikes or anything like that.


– Shows the calories burned while working out and congrats you when you reach your goal calories for the day. Pretty sweet.

With the session it shows the Time of workout and side by side clock which I find is very convenient as I am almost always in a rush. Need to keep track of that time.

3. Charging

I was a little worried when the description didn’t say fast charging. With all the smartphones having quick charge you get used to it. For a smart watch it charges pretty quickly. This is a deal breaker for some, charging is primary.

4. Water

Touch becomes a bit hard in water otherwise Same glare. BUt for that we can use buttons so that is acceptable for a screen that small and its just a watch after all and no 90k smartphone.

5. Music

Connection and all to the bluetooth is cool but sometimes disconnects. Like for a good 2-3 times it didn’t vibrate when the phone rang. Reasons could be I exited the App on the phone. Exiting the app for me is normal as I sometimes I just Clear all the apps. SO that was a bummer for me.

Putting songs on the watch is a bit of a hassle I so wish there was Spotify.

6. Sleep tracking

Probably one of my favourite features in the Versa. I just personally love knowing how much and how well I have slept. I constantly compare my sleep with the average sleep and what should I do to improve it.

7. Women health

It keeps track of your periods. Gives you tips on pre periods acne etc. Handy and useful if you are like me. I have never remembered the date and almost always get that awful surprise. Thanks Fitbit you have made my life easier more than one way.

8. Music

Well I tried putting songs in this. To be honest it isn’t easy. Not at all. Not when you do work mostly on your phone. I miss Spotify. Fitbit are you listening.


9. Miscellaneous

The worst part is when it counts my steps when I am on a bus ride. 30k Steps seriously Fitbit? I am not trail walker. It is too bad. It counts steps when I am in a car etc. So irritating. It throws off my analysis so unbalanced.



Fitbit needs to update the software and fix minor issues like hiked heart rate. Otherwise it is an excellent watch. Wear to the gym, casually to the class, to parties, pool parties, showers and anywhere and everywhere. You’ll love it. No other watch shall look so dapper and efficient in your eyes ever.

If you still want to research more on different options available. Click here for a comprehensive view of other devices.

Buy it now here. Exciting EMI offers available.


Short note on HUMAN LIBARY | Today I learned

human library



What is the Human Library Concept?


In this Library the ‘Books’ are people who have experienced prejudice, social exclusion or stigma and they are borrowed by ‘Readers’ who can ask any question they like, to both learn about the other person and also challenge their own prejudices.


This came about spring of 2000 as a project for Roskilde Festival by Ronni Abergel and his brother Dany and colleagues Asma Mouna and Christoffer Erichsen.


“One good book is equal to hundred good friends but one good friend is equal to a library”. Late Former President APJ Abdul Kalam


This is a reading Session with no filters, no editing, no imagination and everything is real.


Why you should attend this event?


It helps build understanding for diversity by providing a framework for real conversations about important issues.

Open and honest conversations that can lead to greater acceptance, tolerance and social cohesion in the community.


How does this work?


You go into the Human Library and look at the listed ‘Books’ and choose what you want to know about.

Then the protagonist himself/herself tells you the story for  a period of 15-20 minutes.

People who have taken part in these events elsewhere have reported that they can be profound experience for all concerned.


The Human library organisation wrote on their page “ the policemen sitting there speaking with the graffiti writer, the politician in discussions with the youth activist and the football fan in a deep chat with the feminist.” This line is both exciting and ignites the curiosity of someone who enjoys listening to experiences from an entirely different background.


One american says “ I learned about a girl who came here from Nepal” and another says “ I am from religious catholic background and I am gay”. Everybody has a story to tell and hearing it first hand is no less than magic.