Blood pressure monitor using Honeywell 015PDAA5

[Pravi7434]

Hello Guys,
I am new to this forum. I want to make a blood presure monitor using Arduino and Honeywell 015PDAA5 pressure sensor. I very very bad in interpreting a datasheet and need some help to find out how to convert the analog data to meaningful results. I know how to convert an analog signal from the sensor to digital. After that , i dont know exactly what to do? struggling to interpret the datasheet..!!

 

[Gumby_Kevbo]

The pressure sensor data sheet you linked to are digital output devices, either SPI or i2c, so you don't need to convert. You need about 250mmHg full scale or about 5 psi. Don't use too large a range or the 12 bit output won't provide enough resolution.

You need a cuff, a pump, and a leak to bleed off the pressure. These could be a squeeze bulb and leak valve from an old mechanical set.

You need to increase the pressure until the pulsing (due to heart) disappears. Then reduce it slowly until pressure just starts to pulse: This is the systolic pressure. Then you need to monitor the magnitude of the pulsing as you lower the pressure. The peak-peak pulsing will increase until you reach the diastolic pressure, then it will stop increasing. You need to reduce pressure slowly, because you only get about 1 Hz on the pulsing (heart rate) so you will overshoot if you bleed pressure too fast.

 

[Pravi7434]

The pressure sensor data sheet you linked to are digital output devices, either SPI or i2c, so you don't need to convert. You need about 250mmHg full scale or about 5 psi. Don't use too large a range or the 12 bit output won't provide enough resolution.

You need a cuff, a pump, and a leak to bleed off the pressure. These could be a squeeze bulb and leak valve from an old mechanical set.

You need to increase the pressure until the pulsing (due to heart) disappears. Then reduce it slowly until pressure just starts to pulse: This is the systolic pressure. Then you need to monitor the magnitude of the pulsing as you lower the pressure. The peak-peak pulsing will increase until you reach the diastolic pressure, then it will stop increasing. You need to reduce pressure slowly, because you only get about 1 Hz on the pulsing (heart rate) so you will overshoot if you bleed pressure too fast.

Thanks for the replay. I m not using honewell pressure sensore anymore, instead i am using nxp mp3v5050 for better accuracy. Now I know how to calculate pressure from the sensore but i dont know how to calculate the systole and diastole from the captured pressure. Can help me how to calculate the systole and diastole.?
I want to know the mathematics behind the systole and diastole calculation..!!

Thank you

 

[Gumby_Kevbo]

If you could connect the pressure sensor the arteries, then the systolic and diastolic pressure would be the peak and valley of the fluctuating pressure.

http://brooksidepress.org/vitalsign...-2-what-are-systolic-and-diastolic-pressures/

Such a connection is problematic, though, so the pressure is measured indirectly using an arm cuff. The pressure in the cuff is measured. The problem, then, is to determine when the cuff pressure matches the values of interest.

By listening with a stethoscope below the cuff, it can be determined when the pressure in the cuff completely blocks the blood flow to the lower arm. The minimum cuff pressure needed to do this is the systolic reading.

Cuff pressure is slowly reduced until the blood flow is unimpeded. This is the diastolic reading.

But that is the way a human measures the blood pressure, and the listening part is hard for a computer.

Instead of listening for the blood flow, you can closely monitor the cuff pressure waveform. When the cuff pressure Is above the systolic pressure, or below the diastolic pressure, the periodic (with heartbeat) variation in cuff pressure will stop. So you have to control a pump and/or leak to vary the cuff pressure while monitoring and analyzing the pressure readings.

As for calibration, the required pressure range is manageable using a water column, although you will need to do it outside, as most ceilings will be lower than the 10-11 ft you will need to for a 5 psi water column.