oscillometric waveform envelope for mean arterial pressure estimation

Hello,

I am making an oscillometric blood pressure device using arduino and MPXV5050GP sensor. And I am working in the signal processing for a long while, but I can't understand it very well, so I would greatly appreciate if someone could help me. oscillometric method is based on meassuring the peak to peak amplitude of the oscillations of the blood pressure, which are the changes of the cuff pressure during slowly deflating the cuff and the maximum peak to peak value is the mean arterial pressure.

In the following picture in the left are the ploted values of my sensor(attached; the sensor has an output in volts and a I used an analog reference of 3.3 V and the sampling frequency is 1000 Hz). And I have to get my data to look like the picture in the right,making the envelope of the oscillations.

my questions are: how to choose the right filters for my data using fourier transform? and how to make the envelope and measure the peak to peak value?

I tried using the following, but I am not sure if I am doing it right:

1. Bandpass filter (0.5-30 Hz) to extract the deflation line. I am wondering if I chosed the right values because my data is really noisy?

2. detrend the filtered data using detrend function.

2. findpeaks (using min distance and min height thresholds) of the filterd data and the negative(-filtered data)

I tried to make the envelope using the cubic spline, but I didn't get any good ressults

thank you.

[jaydeep panchal]

1) Bandpass filter 0.3 Hz - 3.5 Hz

2) Use Envelope function of MATLAB.

[steven lankheet]

Hello,

I was wondering how you convert your y-values to the corosponding mmHg.

[jaydeep panchal]

Hello,

Conversion into mmHg depends upon pressure sensor type (Analog or Digital) and pressure sensor output units (Kpa, PSI or mmHg)

Regards,

Jaydeep panchal

[Jorge Covas]

Hello,

Im currently working on a oscillometric blood pressure project, could you share your blood pressure simulation?