Arduino ppg coding project

Project functioning:
Sensing heart rate(using PPG sensor) and sending call and message the gps location details when the heart rate falls below certain pre fixed value.
Project Description:
1) User turns device on using a button
2) GPS module gets GPS coordinates and saves in storage
3) Green LED is tumed on and PPG sensor starts
4) PPG sensor continues sensing - if heart rate drops below 48 BPM -trigger alert response as below
Alert response:
a) Green LED is tumed off, Orange LED is turned on
b) Call
c) If user holds button 3 for 5 seconds - call is cancelled or ended
d) If call is cancelled or ended, return to normal flow - turn Orange LED off and turn Green LED on
5) PPG sensor continues sensing - if heart rate drops below 40 BPM -trigger alert response as below
Alarm response:
a) Green LED is turned off. Red LED is turned on
b) Call
c) Send text with GPS coordinates as a link with Google Maps
d) If user holds button 3 for 5 seconds - call is cancelled or ended
e) If call is cancelled or ended, return to normal flow - tum Red LED off and tum Green LED on
6) OFF, if button 1 and button 2 are pressed simultaneously
7) Button 3 to turn the display ON and OFF to show heart rate

Equipment and Sensors used: