BP Clip
The device: Blood Pressure Measurement with Finger Oscillometry
Main goal: Create a low-cost, universal attachment to the smartphone camera that enables people to have their blood pressure measured with a smartphone application.
→ Anywhere, anytime, to anyone.
The feasibility study
To learn and understand the finger oscillometry method for blood pressure estimation, I replicated the work from Chandrasekhar et. al. (2018) entitled "Smartphone-based blood pressure monitoring via the oscillometric finger-pressing method".
In summary, this project involved:
(1) Assembling a prototype device containing a microcontroller Arduino Yun, a PPG sensor (MAX30102), and a force sensor (SingleTactic Calibrated 15mm Diameter, 4.5N/1.0lb Force).
(2) Python software development:
(a) Communicate with the serial to gather real-time data from both sensors.
(b) Replicate the algorithm from Chandrasekhar et al.
(c) Use serial data in the algorithm for oscillogram plot and BP estimation.
(3) Data collection:
(a) Use the prototype to take blood pressure measurements just from our index fingers and
(b) use a 'gold standard' blood pressure device OMRON (7 Series Wireless Upper Arm Blood Pressure Monitor) for BP estimation comparison.
Collected a small data set (N = 30 recordings, 7 people: 4M 3F).
(4) Analysis of results:
(a) The replicated work accurately estimates BP within a certain range, which is not applicable for hypertension individuals and requires a different data modeling.
(b) Proper finger positioning on the platform and pace of applied force are essential for proper data collection and were considered for future implementation.
Outcomes from this study
The findings from this project allowed the development of a universal smartphone attachment, resulting in the published work entitled: "Ultra‑low‑cost mechanical smartphone attachment for no‑calibration blood pressure measurement".