I have been meaning to try out the cooking hacks EHealth Sensor kit for sometime now. My first attempts didn’t go well thanks to the changing supporting libraries and my impatience browsing all forums!

https://www.cooking-hacks.com/documentation/tutorials/ehealth-biometric-sensor-platform-arduino-raspberry-pi-medical.html

Though it was interesting, I was facing a lot of compilation issues since the version I had for the sensor, arduino and the libraries shared by cooking hacks makers were incompatible.

Off late with the second wave of covid, I started using the sensor again. So I thought why not give it a try again to get the data onto internet. This time of course, I was able to get the errors fixed with the below actions

1. Arduino version – I had to delete my Arduino 1.8 version and move back to 1.0.6 old version.
2. Refer to the link and pick up the right version for EHealth and PinChangeInt Libraries based on your time of purchase.

with the above two steps properly done, I was able to compile and upload my code correctly for Arduino Leonardo board.

Now comes the bad part! 😦

1. ReadPulseOximeter() methods was not working! So the interrupt trigger was not working for some reason. I tried changing the pininterrupt library to the latest version. Somehow didn’t help.
2. So I moved the code to Loop() and tried called the C++ method from here directly. While the device display showed the SP02 and BPM accurately, the data I got from the library on Arduino Serial monitor was highly inaccurate!!! I tried changing the libraries and the delay in the eHealth.cpp but with that didn’t change the accuracy of output. Al this while though the device showed proper readings on its native display. I believe it is somehow related to segToNumber method and the delay.

Source code is here (not much different from the existing source code) except for the direct call to Cpp library..

So what next?

-> Investigate the data accuracy issue by updating the Arduino library EHealth file, esp the segToNumber & the delay.

-> Interface the shield to Raspberry PI, use its libraries and see if the accuracy is better than Arduino libraries

Sources:

https://forum.arduino.cc/t/ehealth-with-mega-2560/278026/5

https://www.cooking-hacks.com/forum/viewtopic.php?f=20&t=9984