Commercial Smartwatch VS DIY Heart Rate Monitor

hi there if you are a regular viewer of mine then you might have noticed that I'm always wearing this watch it is actually a hybrid SmartWatch which I got myself two years ago and no this video is not sponsored by them but I have to say that this is a damn good SmartWatch what I like most about it is that it got a heart rate detection built-in which means I can measure my heart rate during working hours and have a look at it through the included smartphone app later on but I noticed that over time the heart rate detection became a bit sluggish and unreliable that is why in this video I will find out how electrical Hardware detection works and afterwards split a small tear by a heart rate monitor in order to ultimately compare its recorded heart rate data to that of my commercial SmartWatch to see whether its data is truly unreliable let's get started this video is sponsored by jl CPC be your one-stop solution for fast PCB production and SMT assembly this starting price for PCBs is only $2.00 and through the DHL delivery option you can get your PCBs even within a week so upload your Gerber files today and try out their service while having a closer look at my commercial smart watch we can easily identify the parts which measures the heart rates it apparently consists of two green LEDs and a small sensor which is positioned between them this part of the watch is always firmly pressed against my skin while being worn so the LEDs basically illuminate my skin while the sensor which is actually a photo detector measures how much light returns from my skin but how does this represent my heart rates well the heart pumps blood through our vessels in kind of like waif-like pulses during those pulses the pressure changes the volume of our vessel slightly and this directly affects how much light gets reflected into the photo detector this way the measured values could look something like this which is also known as a PPG or photo plethysmography and by calculating the time between two or more Peaks we can thus easily get the heart rates of course this was just the super simplified version of the functional principle but you should now at least understand that we firstly need a heart rate sensor which I quickly found on eBay this one is made of the max 3100 which according to its data sheets should be able to do the job just fine and even comes with a nice query interface so I got myself an Arduino Pro Mini and use some simple hookup wire to connect the power and data wires of the sensor to its now of course we could use the information given by the data sheets in order to write our own expert C codes and interact with the sensor registers but we live in the edge of what we know so let's just download a library for the sensor and try one of its examples to upload it to the board I used an FTDI break outs set to a 3.3 volts which I simply pushed into the arduino pro mini specie beer and clicked uploads as soon as the upload was done the red LED of the sensor lit up and thus I press my finger onto it and opens the serial monitor and as you can see this answer seems to detect my heart rates more or less accurately if I use my smart watch as a reference but I quickly noticed that we would also need some algorithms to get a stable heart rate from the measured values and your skin also needs to be pressed firmly against the sensor in order to get accurate humans those observations party let's to problems though because the sensor is not eat all's components on its breakout piece bian which means that when I will let our design a custom housing for its it will never be able to firmly press against my skin that is why I dropped the sensor and instead look for an alternative which I quickly found in the form of this groove a heart rate sensor from seed studio this system basically combines a pah age 0:01 AI a heart rate sensor with an STM 32 microcontroller which not only performs algorithms to calculate a stable heart rates but also offers a nice Percy interface for easy an Arduino integration to test it I plugged in its included connector and soldered all the wires to that we know after then uploading the given example codes this sensor system woke up and thus and once again placed my finger onto the sensor by once again opening the serial monitor I noticed that it took a bit longer to get a proper heart rate value but as soon as a transmitted one it seemed to be pretty accurate and stable if we once again compare it to my SmartWatch now of course this system is not ready for proper testing yet because it still needs an OLED display a battery with 3.3 volt regulator and the switch for power and micro SD card module to lock my heart rates so I created this schematic for the task at hand and continued by soldering all the components to one another according to its through the help of some hookup wire as soon as that was done I wrote a bit of Arduino codes for which I used the total of three different libraries and uploaded it to the finished system and as you can see the ohlet's shows me the current heart rate every seconds and if we remove the micro SD cards then we can see that the Arduino also perfectly locked all the display values last but not least it was time for me to design a case for that we know system in fusion 360 year as soon as I was happy with the results I had 3d printed ads with my pooza I three mark three year edits an elastic band to it and placed all the electronics in sites which I then temporarily secured move a bit of hot glue and after adding both housings to my arm and checking whether everything still work fine it was time to also start my SmartWatch and finally head out sights to go for run I ran for about 30 minutes and noticed quite a few problems with the gry system but more about that in a second first off I had to import the recorded values into Excel in order to create this beautiful graph at first the DIY system worked pretty well but it somehow got stuck at 160 BPM and afterwards dropped down to around 80 BPM even though I was at around 140 bpm however after repositioned the sensor doing my run attract my heart rate pretty accurately if I compare it to the SmartWatch data which only comes with minor differences so that basically means since both measured values are about the same my SmartWatch seems to still work just fine which is really for me if you also relieved and enjoyed the video then don't forget to Like share subscribe and hit the notification bar stay creative and I will see you next time

Channel: GreatScott!

Views: 199,958

Keywords: heart, rate, monitor, smartwatch, diy, commercial, tutorial, how, to, make, project, guide, beginner, beginners, explain, measure, bpm, optical, electric, led, light, photo, detector, sensor, wave, pulse, pressure, volume, reflect, compare, comparison, ppg, photoplethysmography, time, calculate, max30100, arduino, pro, mini, library, grove, seeed, studio, stm32, i2c, oled, lipo, battery, portable, regulator, micro, sd, card, fusion360, 3d, printing, log, test, greatscott, greatscott!, electronic, electronics

Id: ViYAr-M4i0s

Length: 8min 28sec (508 seconds)

Published: Sun Apr 26 2020