Blood Pressure Basics
Classification of blood pressure for adults (18 years and older
BP Sensor
How the System Works
Demo Video

Published June 27, 2021 © GPL3+

Blood Pressure Sensor Interfacing with Raspberry Pi

Blood pressure measuring and Detailed Report Emailing system using Raspberry Pi.

IntermediateFull instructions provided6 hours9,702

Blood Pressure Sensor Interfacing with Raspberry Pi

Things used in this project

Hardware components

Raspberry Pi 3 Model B

Linear Regulator (7805)

Capacitor 470 µF

5 mm LED: Red

Bridge rectifier

9V 1A Switching Wall Power Supply

Blood Pressure Sensor

Through Hole Resistor, 470 ohm

TaydaElectronics DC POWER JACK 2.1MM BARREL-TYPE PCB MOUNT

5 volt 2 amp dc adapter for raspberry pi

Software apps and online services

Raspberry Pi Raspbian

Hand tools and fabrication machines

Soldering iron (generic)

Solder Wire, Lead Free

Solder Flux, Soldering

Story

A blood pressure monitoring system provides a useful tool for users to measure and manage their daily blood pressure values. This system can measure the blood pressure and heart rate and then store and forward the measuring information to the management through email. The email will contain the details of the blood pressure in a text file. the text file contains the details of the systolic, diastolic, and heart rates details.

In this project, I have created the classification of blood pressure and Emailing system using raspberry pi and BP Sensor

Blood Pressure Basics

Blood pressure is the pressure of the blood in the arteries as it is pumped around the body by the heart. When your heart beats, it contracts and pushes blood through the arteries to the rest of your body. This force creates pressure on the arteries. Blood pressure is recorded as two numbers— the systolic pressure (as the heart beats) over the diastolic pressure (as the heart relaxes between beats). The unit which measures this is called a Sphygmomanometer.

Monitoring blood pressure at home is essential for many people, especially if you have high blood pressure. Blood pressure does not stay the same all the time. It changes to meet your body’s needs. It is affected by various factors including body position, breathing or emotional state, exercise, and sleep. It is best to measure blood pressure when relaxed and sitting or lying down.

Classification of blood pressure for adults (18 years and older)

classification of Blood pressure

Block Diagram of the System

Block Diagram

Blood pressure monitoring and detailed Emailing System Image

All The BP Sensors available in the market are unsuitable to interface with the external microcontroller. Here I have used a Customized Bp sensor interface with the raspberry pi.

BP Sensor

Wrist Bp sensor

Here I have used a wrist wearable Blood pressure sensor. The sensor gives the data Output Through UART Communication.

Features

Intelligent automatic compression and decompression
Easy to operate, switching button to start measuring
60 store groups memory measurements
Can read single or all measures
3 minutes the automatic power-saving device
Intelligent device debugging, automatic power to detect
Local tests for wrist circumference as 135-195mm
Large-scale digital liquid crystal display screen, Easy to Read Display
Fully Automatic, Clinical Accuracy, High-accuracy
Power by External +5V DC
Serial output data for external circuit processing or display.

Specification

Working Voltage: +5V, 200mA regulated
Output Format:Serial Data at 9600 baud rate(8 bits data, No parity, 1 stop bits). Outputs three parameters in ASCII.

The sensing unit wire length is 2 meters

Sensor Pinouts

TX-OUT = Transmit output. Output serial data of 3V logic level, Usually connected to RDX pin of microcontrollers/RS232/USB-UART.
+5V = Regulated 5V supply input.
GND = Board Common Ground
Status = Indicates whether the BP sensor is active or Not.

Correct way of using The BP sensor

How the System Works.

Raspberry pi 3 B+ Is used in this project to receive the data from the BP Sensor and to process the data. The BP sensor provides the data through the UART Communication to Raspberry pi. The raspberry pi receives the data from the sensor Through the UART channel, The Sensor Baud rate is fixed to 9600 hence we need to set the baud rate settings of the Raspberry pi to 9600.

The output reading is an 8-bit value in ASCII format with fixed digits, from 000 to 255.

Typical reading will be like below where the three values are separated by a comma and space.

Systolic
Diastolic
Pulse

Example: 129, 107, 095

We have used Terminal software to view reading, You can use any other software also which allows connecting to COM port and view/process data.

After Converting the values the data is classified by comparing the systolic and diastolic data according to Standard format.

For Emailing the report I have stored the converted data in a text format. after the classification, the file will be attached to the Email By creating subject details according to the Blood pressure data. For email, I have used SMTP Libraries.

Text File Screenshot

Email Screenshot

Demo Video

Code

project code

import serial, time
import RPi.GPIO as GPIO
import re
import smtplib,ssl  
from email.mime.multipart import MIMEMultipart  
from email.mime.base import MIMEBase  
from email.mime.text import MIMEText  
from email.utils import formatdate  
from email import encoders

bp = 2 // Bp sensor status pin 
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)
GPIO.setup(bp,GPIO.IN)
ser = serial.Serial("/dev/ttyS0",9600)
ser.bytesize = serial.EIGHTBITS #number of bits per bytes
ser.parity = serial.PARITY_NONE #set parity check: no parity
ser.stopbits = serial.STOPBITS_ONE #number of stop bits
ser.timeout = 1            #non-block read
ser.xonxoff = False     #disable software flow control
ser.rtscts = False     #disable hardware (RTS/CTS) flow control
ser.dsrdtr = False       #disable hardware (DSR/DTR) flow control
file = open('sensor_readings.txt', 'w')
#file.write('time and date, systolic(b), diastolic(c),Pulse(d)\n')
file.write(' Your Blood Pressure Details Are As Follows\n')


def send_an_email_normal():  
    toaddr = 'to@gmail.com'      # To id 
    me = 'your email id'          # your id
    subject = "Normal Blood pressure"              # Subject
    msg = MIMEMultipart()  
    msg['Subject'] = subject  
    msg['From'] = me  
    msg['To'] = toaddr  
    msg.preamble = "test "   
    #msg.attach(MIMEText(text))  
  
    part = MIMEBase('application', "octet-stream")  
    part.set_payload(open("sensor_readings.txt", "rb").read())  
    encoders.encode_base64(part)  
    part.add_header('Content-Disposition', 'attachment; filename="sensor_readings.txt"')   # File name and format name
    msg.attach(part)  
  
    try:  
       s = smtplib.SMTP('smtp.gmail.com', 587)  # Protocol
       s.ehlo()  
       s.starttls()  
       s.ehlo()  
       s.login(user = 'mailto:xxxxx@gmail.com', password = 'your email password')  # User id & password
       #s.send_message(msg)  
       s.sendmail(me, toaddr, msg.as_string())  
       s.quit()  
    #except:  
    #   print ("Error: unable to send email")    
    except SMTPException as error:  
          print ("Error")                # Exception
          
def send_an_email_Hypotension():  
    toaddr = 'to@gmail.com'      # To id 
    me = 'mailto:your email id'          # your id
    subject = "Hypotension"              # Subject
    msg = MIMEMultipart()  
    msg['Subject'] = subject  
    msg['From'] = me  
    msg['To'] = toaddr  
    msg.preamble = "test "   
    #msg.attach(MIMEText(text))  
  
    part = MIMEBase('application', "octet-stream")  
    part.set_payload(open("sensor_readings.txt", "rb").read())  
    encoders.encode_base64(part)  
    part.add_header('Content-Disposition', 'attachment; filename="sensor_readings.txt"')   # File name and format name
    msg.attach(part)  
  
    try:  
       s = smtplib.SMTP('smtp.gmail.com', 587)  # Protocol
       s.ehlo()  
       s.starttls()  
       s.ehlo()  
       s.login(user = 'mailto:xxxxx@gmail.com', password = 'your email password') # User id & password
       #s.send_message(msg)  
       s.sendmail(me, toaddr, msg.as_string())  
       s.quit()  
    #except:  
    #   print ("Error: unable to send email")    
    except SMTPException as error:  
          print ("Error")                # Exception
          
def send_an_email_prehypertension():  
    toaddr = 'to@gmail.com'      # To id 
    me = 'mailto:your email id'          # your id
    subject = "Prehypertension"              # Subject
    msg = MIMEMultipart()  
    msg['Subject'] = subject  
    msg['From'] = me  
    msg['To'] = toaddr  
    msg.preamble = "test "   
    #msg.attach(MIMEText(text))  
  
    part = MIMEBase('application', "octet-stream")  
    part.set_payload(open("sensor_readings.txt", "rb").read())  
    encoders.encode_base64(part)  
    part.add_header('Content-Disposition', 'attachment; filename="sensor_readings.txt"')   # File name and format name
    msg.attach(part)  
  
    try:  
       s = smtplib.SMTP('smtp.gmail.com', 587)  # Protocol
       s.ehlo()  
       s.starttls()  
       s.ehlo()  
       s.login(user = 'mailto:xxxxx@gmail.com', password = 'your email password') # User id & password
       #s.send_message(msg)  
       s.sendmail(me, toaddr, msg.as_string())  
       s.quit()  
    #except:  
    #   print ("Error: unable to send email")    
    except SMTPException as error:  
          print ("Error")                # Exception
          
def send_an_email_stage1():  
    toaddr = 'to@gmail.com'      # To id 
    me = 'mailto:your email id'          # your id
    subject = "Stage 1 Hypertension"              # Subject
    msg = MIMEMultipart()  
    msg['Subject'] = subject  
    msg['From'] = me  
    msg['To'] = toaddr  
    msg.preamble = "test "   
    #msg.attach(MIMEText(text))  
  
    part = MIMEBase('application', "octet-stream")  
    part.set_payload(open("sensor_readings.txt", "rb").read())  
    encoders.encode_base64(part)  
    part.add_header('Content-Disposition', 'attachment; filename="sensor_readings.txt"')   # File name and format name
    msg.attach(part)  
  
    try:  
       s = smtplib.SMTP('smtp.gmail.com', 587)  # Protocol
       s.ehlo()  
       s.starttls()  
       s.ehlo()  
        s.login(user = 'mailto:xxxxx@gmail.com', password = 'your email password') # User id & password
       #s.send_message(msg)  
       s.sendmail(me, toaddr, msg.as_string())  
       s.quit()  
    #except:  
    #   print ("Error: unable to send email")    
    except SMTPException as error:  
          print ("Error")                # Exception

def send_an_email_stage2():  
    toaddr = 'to@gmail.com'      # To id 
    me = 'mailto:your email id'          # your id
    subject = "Stage 2 Hypertension"              # Subject
    msg = MIMEMultipart()  
    msg['Subject'] = subject  
    msg['From'] = me  
    msg['To'] = toaddr  
    msg.preamble = "test "   
    #msg.attach(MIMEText(text))  
  
    part = MIMEBase('application', "octet-stream")  
    part.set_payload(open("sensor_readings.txt", "rb").read())  
    encoders.encode_base64(part)  
    part.add_header('Content-Disposition', 'attachment; filename="sensor_readings.txt"')   # File name and format name
    msg.attach(part)  
  
    try:  
       s = smtplib.SMTP('smtp.gmail.com', 587)  # Protocol
       s.ehlo()  
       s.starttls()  
       s.ehlo()  
       s.login(user = 'mailto:xxxxx@gmail.com', password = 'your email password') # User id & password
       #s.send_message(msg)  
       s.sendmail(me, toaddr, msg.as_string())  
       s.quit()  
    #except:  
    #   print ("Error: unable to send email")    
    except SMTPException as error:  
          print ("Error")                # Exception
          
def send_an_email_hypertensive():  
    toaddr = 'to@gmail.com'      # To id 
    me = 'mailto:your gmail id'          # your id
    subject = "Hypertensive Crisis"              # Subject
    msg = MIMEMultipart()  
    msg['Subject'] = subject  
    msg['From'] = me  
    msg['To'] = toaddr  
    msg.preamble = "test "   
    #msg.attach(MIMEText(text))  
  
    part = MIMEBase('application', "octet-stream")  
    part.set_payload(open("sensor_readings.txt", "rb").read())  
    encoders.encode_base64(part)  
    part.add_header('Content-Disposition', 'attachment; filename="sensor_readings.txt"')   # File name and format name
    msg.attach(part)  
  
    try:  
       s = smtplib.SMTP('smtp.gmail.com', 587)  # Protocol
       s.ehlo()  
       s.starttls()  
       s.ehlo()  
       s.login(user = 'mailto:xxxxx@gmail.com', password = 'your email password') # User id & password
       #s.send_message(msg)  
       s.sendmail(me, toaddr, msg.as_string())  
       s.quit()  
    #except:  
    #   print ("Error: unable to send email")    
    except SMTPException as error:  
          print ("Error")                # Exception
        
while True:
    response = ser.readline().decode('ASCII')
    x = len(response)# checking the avalible bytes in the serial data
    if x >= 10:
        print("systolic,diastolic,Pulse")
        print(response)
        y = response.split(',') #spliting the each bytes with comma
        print(y)
        z = re.findall('[0-9]+', response) # extracting each byte
        print(z)
        a = [z] # creating extracted each byte in a array
        b = int(z[0]) # first byte in a array (Systollic)
        c = int(z[1]) # second byte in a array (diastollic)
        d = int(z[2]) # third byte in a array (pulse)
        print("Systolic :", b)
        print("Diastollic :",c)
        print("Pulse:" , d)
        file.write(time.strftime('%H:%M:%S %d/%m/%Y') + '   Systollic:' + str(b) + '  Diastollic:'+ str(c)+'  Pulse rate:' + str(d) + '\n')
        time.sleep(1)
        file.close()
        print("file written")
        if b < 90 and c < 60:
            print('Hypotension')
            send_an_email_Hypotension()
            
        if b > 120 and b < 139 and c > 80 and c < 90:
            print('Prehypertension')
            send_an_email_prehypertension()
    
        if b > 140 and b < 159 and c > 90 and c < 99:
            print('stage 1 Hypertension')
            send_an_email_stage1()
            
        if b > 160 and b < 179 and c > 100 and c < 109:
            print('stage 2 Hypertension')
            send_an_email_stage2()
            
        if b > 180 and c > 110:
            print('Hypertensive Crisis')
            send_an_email_hypertensive()
        
        else:
            send_an_email_normal()
            print('sent_the_mail')

Credits

vinay y.n

26 projects • 45 followers

An electronic product engineer with 8 years of experience in the field. The passion for electronics began as a hobby 11 years ago.

Blood Pressure Sensor Interfacing with Raspberry Pi