Hi sir.
It is possible to detect some (not all) diseases (for example problems with heart) by using machine learning algorithms.

Regards,
sdizdarevic

Dear Demetris,

By circuitry of the sensor you mean sensor schematic? The schematic of the sensor is on the link below:
https://cdn.shopify.com/s/files/1/0100/6632/files/PulseSensorAmpd_-_Schematic.pdf?1862089645030619491
Here is a link to the PCB design files : https://github.com/WorldFamousElectronics/PulseSesorAmped_Hardware/raw/master/PulseSensorAmped%20Hardware.zip
Basic parts of the sensor circuit are ambient light sensor from Avago (http://www.avagotech.com/docs/AV02-1169EN), and green super bright reverse mount LED from Kingbright (http://www.kingbrightusa.com/images/catalog/SPEC/am2520zgc09.pdf). I think you can use any ambient light sensor which is simmilar to Avagos sensor, but the output of the sensor is very sensitive, to the color of the LED light, so you need to get the green LED from Kingbright if you want to build your sensor.
I live and work in Bosnia and Herzegovina.
God bless you too.
Regards,
Saudin
You can see some of my projects and writings on my blog: sdizdarevic.com.

Hi demetrios! Thank you for contacting me. The circuitry of the sensor is very simple. You can obtain a sensor from pulsesensor.com. I am not related to the company. I would like to send you my sensor, but the shipping costs from my country are really high. If you need more info, feel free to ask. By the way, I am also electronics enginner and I've obtained masters degree (masters of science, field of automation control and electronics) in my native country.