In [ ]:

    

import time
import RPi.GPIO as GPIO
 
GPIO.setmode(GPIO.BCM)
# read SPI data from MCP3008 chip, 8 possible adc's (0 thru 7)
def readadc(adcnum, clockpin, mosipin, misopin, cspin):
    if ( (adcnum > 7) or (adcnum < 0) ):
        return -1
    GPIO.output(cspin, True)
    GPIO.output(clockpin, False) # start clock low
    GPIO.output(cspin, False) # bring CS low
    
    commandout = adcnum
    commandout |= 0x18 # start bit + single-ended bit
    commandout <<= 3 # we only need to send 5 bits here
    
    for i in range(5):
        if (commandout & 0x80):
            GPIO.output(mosipin, True)
        else:
            GPIO.output(mosipin, False)
        commandout <<= 1
        GPIO.output(clockpin, True)
        GPIO.output(clockpin, False)
    
    adcout = 0
    
    # read in one empty bit, one null bit and 10 ADC bits
    for i in range(12):
        GPIO.output(clockpin, True)
        GPIO.output(clockpin, False)
        adcout <<= 1
        if (GPIO.input(misopin)):
            adcout |= 0x1
    GPIO.output(cspin, True)
    
    adcout >>= 1 # first bit is 'null' so drop it
    return adcout

# change these as desired - they're the pins connected from the
# SPI port on the ADC to the Raspberry Pi</h1>
SPICLK = 18
SPIMISO = 23
SPIMOSI = 24
SPICS = 25

GPIO.setwarnings(False)
#set up the SPI interface pins
GPIO.setup(SPIMOSI, GPIO.OUT)
GPIO.setup(SPIMISO, GPIO.IN)
GPIO.setup(SPICLK, GPIO.OUT)
GPIO.setup(SPICS, GPIO.OUT)

#pulse sensor connected to adc #0
pulse_adc = 0
#Threshold for pulse sensing (half of values between 0-1023)
THRESH = 512


    

In [ ]:

    

#Pulse graph
pulse = False
THRESH = 512

while True:
    #read the analog pin
    analog_value = readadc(pulse_adc, SPICLK, SPIMOSI, SPIMISO, SPICS)
    #draw the equivalent number of points in an attempt to draw a vertical pulse sensing graph
    output = int(analog_value / 100) * "."
    #detect beats
    if (analog_value > THRESH):
        if (pulse == False):
            pulse = True
            output += " Beat {}".format(analog_value)
    else:
        pulse = False
    print(output)
    #hang out and do nothing for a tenth of a second
    time.sleep(0.1)


    

In [ ]:

    

#BPM
previous_seconds = time.time()

while True:
    #read the analog pin
    analog_value = readadc(pulse_adc, SPICLK, SPIMOSI, SPIMISO, SPICS)
    if (analog_value > THRESH):
        if (pulse == False):
            pulse = True
            new_seconds = time.time()
            duration = new_seconds - previous_seconds
            print(analog_value)
            print(60 / duration)
            previous_seconds = new_seconds
    else:
        pulse = False
    time.sleep(0.01)