Iteration 3 Conor Gleeson


Iteration 3 

Improvments to this iteration

This week we began with a new version of the code to test. This latest version included a display on the microbit showing th epulse rate of th user and helps the user apply the correct amount of pressure to the sensor and get their postioning correct. With this done they can then press the A button to calibrate the readings to the highest and lowest points in order to get an even HRV reading. The code now also includes a 4 second in 6 second out pacer on the serial output to help the user focus on their breathing. When everything is set up correctly and the pacer is being followed the HRV can be seen to come closer in phase to the breathing pacer showing the effect of breathing on HRV. Even if the two readings cannot be gotten into phase the user can see the HRV graph adjust as their breathing changes, as they slow it, speed up, yawn or talk. It was also clear that the pressure and positiong needed for a clear reading varied greatly from person to person and seemed to work better for some.

Issues

One issue with this current version is the sensitivity and reliablity of the sensor. It is very finiky for the user to get their finger positioned correctly on the sensor with the correct amount of pressure. The display on the MicroBit is useful to show when the correct position and pressure is found but it is very easy for this to be lost with even the slighest movement.

 


 

https://youtu.be/bn5EhxWaljE

Next Iteration

For the next iteration the major issue to be fixed is the sensetivity of the sensor to movment and pressure. This could possibly be done by tracking. We could possibly do this by tracking the peaks and valleys of the HRV and normalizing the data to ensure a smoother reading. We could also possibly add a threshold to the display that if the value change detected is clearly too great it that it was clearly caused by a loss in reading from movemnt, if the change is outside the threshold it could eb ignored to avoid big dips in the reading being displayed.




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