PulseFit-Pulse Sensor with AutoAdjusted Threshold

I've been working on this PCB off-line for a while now. Since originally posting this project, one of my students has been working on developing a PulseFit GFX board that allows the user to view the pulse waves in real-time. You can check out the schematic here: I still have a few things to tidy-up on the board layout, but it's almost there.

Submitted to Flexible PCB Concept Contest. I would like to experiment with moving the sensor to different parts of the body similar to ideas presented in my ring-based heart rate monitor, my wrist-worn heart rate monitor, or my finger clip heart rate monitor projects also shared on Hackaday. Such prototypes would require flexible PCBs to properly match the body's contours to main the signal. I've even published a research article on one of my wrist-worn heart and respiratory rate wrist-worn heart and respiratory rate monitors (please feel free to message me for a PDF of the full article). The Flexible PCB Contest would help me take my project further and advance my study into body-worn sensors.

Made my second @oshpark order for PulseFit. This version uses bottom entry SMD LEDs instead of the through hole types. I hoping to start selling these soon so having all surface mount components will make assembly a lot easier.

Sent PCB to @oshpark Here's the link to order the board yourself.

Link to the .brd and .sch files on GitHub.

I just need to organize the silkscreen a bit and I may re-adjust how I did the ground plane. The photodiodes are in the center of the heart. I will be using reflectance photoplethysmography as opposed to transmission photoplethysmography so I don't have to build a finger cuff. Can't wait to send this off to @oshpark!

My project was Featured on Instructables! Check out that gold ribbon.