Biomedical-Learning-Kit/project1_stpe2.py at main · eimtechnology/Biomedical-Learning-Kit · GitHub

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"""
This file is the example code for the project1: blood oximter
"""

#import Pin and SoftI2C class for communication
from machine import SoftI2C, Pin, SPI
#import class to control pulse oximeter, import constant for light level
from max30102 import MAX30102, MAX30105_PULSE_AMP_MEDIUM
from time import sleep
#import AcDcCalculator class and calculate_SpO2 function
from SpO2Calculators import AcDcCalculator
#impor NeoPixel class for RGB LEDs
from neopixel import NeoPixel
import st7789# type: ignore
from font import vga1_16x32 as font1
from font import vga2_8x8 as font2

WIDTH, HEIGHT = 240, 240
 # SCK = SCL
 # MOSI = SDA
BACKLIGHT_PIN = 20
RST_PIN = 16
DC_PIN = 21
CS_PIN = 17
SCK_PIN = 18 #SCL
MOSI_PIN = 19#SDA
SPI_NUM = 0

spi = SPI(SPI_NUM, baudrate=31250000, sck=Pin(SCK_PIN), mosi=Pin(MOSI_PIN))
tft = st7789.ST7789(
    spi, WIDTH, HEIGHT,
    reset=Pin(RST_PIN, Pin.OUT),
    cs=Pin(CS_PIN, Pin.OUT),
    dc=Pin(DC_PIN, Pin.OUT),
    #backlight=Pin(BACKLIGHT_PIN, Pin.OUT),
    rotation=0,
)

#set adaptive threshold value to 35%
red_calculator = AcDcCalculator(0.35)
ir_calculator = AcDcCalculator(0.35)

tft.fill(st7789.WHITE)

#I2C object for pulse oximeter object, make sure sda and scl pins match your wiring
i2c = SoftI2C(sda = Pin(26), scl = Pin(27), freq = 400000)

#pulse oximeter object to communicate with sensor
oximeter = MAX30102(i2c)

rgb_leds = NeoPixel(Pin(23), 4)

#scan for sensor and connect if found
if oximeter.i2c_address not in i2c.scan():
    tft.text(font1,str("Sensor not found."),8,8,st7789.color565(255,0,0))
    print("Sensor not found.")
    exit()
elif not oximeter.check_part_id():
    tft.text(font1,str("I2C device ID not corresponding to MAX30102"),8,8,st7789.color565(255,0,0))
    print("I2C device ID not corresponding to MAX30102")
    exit()
else:
    tft.text(font1,str("Sensor found, connecting"),8,8,st7789.color565(255,0,0))
    print("Sensor found, connecting")

#set up sensor with default settings
oximeter.setup_sensor()

#change light level setting to "medium"
oximeter.set_active_leds_amplitude(MAX30105_PULSE_AMP_MEDIUM)

#set frequency at which samples are take (400 times/second)
oximeter.set_sample_rate(400)

# Set the number of samples to be averaged per each reading
oximeter.set_fifo_average(8)


#variable to track samples read
samples_n = 0
#variable to track SpO2 percentage
SpO2 = 91
while True:
    #gather data from sensor's internal FIFO memory queue
    oximeter.check()

    #if the gathered data contains samples
    if oximeter.available():

        #take 1 red and ir light sample from the data gathered
        red_reading = oximeter.pop_red_from_storage()
        ir_reading = oximeter.pop_ir_from_storage()

        #increment counter by 1 since we read a new sample
        samples_n = samples_n + 1

        #if a finger is on the sensor
        if red_reading > 9000 and ir_reading > 14000:
            #find peaks and valleys in ir and red PPG waves
            red_result = red_calculator.peak_valley_detection(red_reading, samples_n)
            ir_calculator.peak_valley_detection(ir_reading, samples_n)

            #start calculating SpO2 after 100 samples, this is done to calibrate thresholds
            if samples_n > 100:
                #calculate AC/DC ratios
                ir_ratio = ir_calculator.calculate_ratio()
                red_ratio = red_calculator.calculate_ratio()

                #if the ratios calculate a valid result
                if ir_ratio != None and red_ratio != None:
                    #print and calculate SpO2 using AC/DC ratios
                    SpO2 = 104 - 17 * (red_ratio / ir_ratio)
                    tft.text(font1,str("SpO2:       "),8,8,st7789.color565(255,0,0))
                    tft.text(font1,str(SpO2),8,48,st7789.color565(255,0,0))
                    print("SpO2 calculation: ", SpO2)

            else:
                tft.text(font1,str("Calibrating"),8,8,st7789.color565(255,0,0))
                print("Calibrating")
        else:
            #reset calculators and sample number
            samples_n = 0
            red_calculator.reset()
            ir_calculator.reset()
            #wait 5 seconds for sensor to read finger so that if there's a finger is on the next reading, it had enough time to settle
            tft.text(font1,str('Delay          '),8,8,st7789.color565(255,0,0))
            tft.text(font1,str('               '),8,8,st7789.color565(255,0,0))
            print('Delay')
            sleep(5)

    if SpO2 < 90:
        rgb_leds.fill((16,0,0))
    elif SpO2 > 90 and SpO2 < 95:
        rgb_leds.fill((16,12,0))
    elif SpO2 > 95:
        rgb_leds.fill((0,16,0))
    rgb_leds.write()