App not updating while in background

Need Help With My Project
1

I am making a Raspberry Pi weather station that uploads its data using Blynk. I recently discovered that the weather station is only uploading data to the Blank app when the app is running. Shortly after I close the app (hit the home button), the weather station stops uploading data. This leads to my Supercharts missing large chunks of data. I also have a lightning detector set up to send notifications with a time stamp when it detects a lightning strike; however, I only receive the notification when I open the app and the time stamp isn’t when the strike occurred but rather when I opened the app. I am using the python Blynk library. I am also using the latest iOS app. I would greatly appreciate any help as I am new to coding and Blynk. Here is my code for the Raspberry Pi.


import BlynkLib_Outdoor
import time
import Adafruit_TCS34725
from Adafruit_BME280 import *
from RPi_AS3935 import RPi_AS3935
import SI1145.SI1145 as SI1145
import RPi.GPIO as GPIO
from datetime import datetime
import smbus


BLYNK_AUTH = 'This is where my token normally is'

# Initialize Blynk
blynk = BlynkLib_Outdoor.Blynk(BLYNK_AUTH)

# Initialize Lightning detector
as3935 = RPi_AS3935(address=0x03, bus=1)
as3935.set_indoors(True)
as3935.set_noise_floor(0)
time.sleep(0.005)
as3935.calibrate(tun_cap=2)
time.sleep(0.005)
as3935LastInterrupt = 0
as3935LightningCount = 0
as3935LastDistance = 0
as3935LastStatus = ""
GPIO.setmode(GPIO.BCM)
as3935Interrupt = False


def process_as3935_interrupt():

    global as3935Interrupt
    global as3935, as3935LastInterrupt, as3935LastDistance, as3935LastStatus

    as3935Interrupt = False

    reason = as3935.get_interrupt()

    time.sleep(0.003)

    as3935LastInterrupt = reason

    if reason == 0x00:
        now = datetime.now().strftime('%H:%M:%S - %m/%d')
        as3935LastStatus = "Spurious Interrupt %s" % now
    elif reason == 0x01:
        now = datetime.now().strftime('%H:%M:%S - %m/%d')
        as3935LastStatus = "Noise Floor too low - adjusting (%s)" % now
        as3935.raise_noise_floor()
    elif reason == 0x04:
        now = datetime.now().strftime('%H:%M:%S - %m/%d')
        as3935LastStatus = "Disturber detected - masking (%s)" % now
        as3935.set_mask_disturber(True)
    elif reason == 0x08:
        now = datetime.now().strftime('%H:%M:%S - %m/%d')
        distance = as3935.get_distance()
        as3935LastDistance = distance
        as3935LastStatus = "Lightning Detected " + str(distance) + "km away. (%s)" % now

    blynk.virtual_write(6, as3935LastStatus)
    blynk.notify(as3935LastStatus)


def handle_as3935_interrupt(channel):
    global as3935Interrupt

    blynk.virtual_write(6, "as3935 Interrupt")

    as3935Interrupt = True


as3935pin = 17

GPIO.setup(as3935pin, GPIO.IN)
GPIO.add_event_detect(as3935pin, GPIO.RISING, callback=handle_as3935_interrupt)

# Other sensors 


@blynk.VIRTUAL_READ(1)
def v1_read_handler():
    sensor_1 = BME280(t_mode=BME280_OSAMPLE_8, p_mode=BME280_OSAMPLE_8, h_mode=BME280_OSAMPLE_8)
    degrees = sensor_1.read_temperature_f()
    blynk.virtual_write(1, '{0:0.1f}'.format(degrees))


@blynk.VIRTUAL_READ(2)
def v2_read_handler():
    sensor_2 = BME280(t_mode=BME280_OSAMPLE_8, p_mode=BME280_OSAMPLE_8, h_mode=BME280_OSAMPLE_8)
    # atm = sensor.read_pressure_atm()
    pascals = sensor_2.read_pressure()
    hectopascals = pascals / 100
    blynk.virtual_write(2, '{0:0.0f}'.format(hectopascals))


@blynk.VIRTUAL_READ(3)
def v3_read_handler():
    sensor_3 = BME280(t_mode=BME280_OSAMPLE_8, p_mode=BME280_OSAMPLE_8, h_mode=BME280_OSAMPLE_8)
    humidity = sensor_3.read_humidity()
    blynk.virtual_write(3, '{0:0.1f}'.format(humidity))


@blynk.VIRTUAL_READ(4)
def v4_read_handler():
    tcs = Adafruit_TCS34725.TCS34725(integration_time=Adafruit_TCS34725.TCS34725_INTEGRATIONTIME_154MS,
                                     gain=Adafruit_TCS34725.TCS34725_GAIN_4X)
    tcs.set_interrupt(False)
    r, g, b, c = tcs.get_raw_data()
    lux = Adafruit_TCS34725.calculate_lux(r, g, b)
    blynk.virtual_write(4, lux)


@blynk.VIRTUAL_READ(5)
def v5_read_handler():
    sensor_4 = SI1145.SI1145()
    vis = sensor_4.readVisible()
    IR = sensor_4.readIR()
    uv = sensor_4.readUV()
    uvindex = uv / 100.0
    blynk.virtual_write(5, uvindex)


@blynk.VIRTUAL_READ(6)
def v6_read_handler():
    if as3935Interrupt == True:
        process_as3935_interrupt()


# Start Blynk 


blynk.run()
2

Do you use Blynk Cloud?

3

Yes

4

In that case this is expected. VIRTUAL_READ handlers are triggered only when the app is active. You may change this with the local server with allow.reading.widget.without.active.app=true option. Otherwise, you need to use some kind of timer within your code that will trigger VIRTUAL_READ.

At some point we will also enable this on the server side on the Blynk Cloud.

5

Thank you so much for helping me out. This was really bugging me. So how could I use a timer to trigger the VIRTUAL_READ handler?