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Migrate sensors from Cayenne to Blynk

Hello,
I’m new to Blynk. I’m not programmer. I start to learn Arduino course from Forbot. I try Blynk app and make my first project with Blynk (ESP32+DHT11) and it works great. I have also one project in Cayenne MyDevices: Raspberry Pi Zero + SDS011 sensor + BME680 sensor (Cayenne Admin help me with coding). I use old Tablet with Android 4.4.2 but last days Cayenne App stop working on that system and Blynk works great. My question is that: is it possible to change code to work also on Blynk? It’s possible to sensors send data to Cayenne and Blynk or I have to delete Cayenne lines of code and add Blynk code? I don’t want to delete Cayenne, I just want to try how will Blynk work with that sensors.

My code for SDS011:

#!/usr/bin/python -u
# coding=utf-8
# "DATASHEET": http://cl.ly/ekot
# https://gist.github.com/kadamski/92653913a53baf9dd1a8
from __future__ import print_function
import serial, struct, sys, time, json, subprocess
import cayenne.client
import time
import logging

# Cayenne authentication info. This should be obtained from the Cayenne Dashboard.
MQTT_USERNAME  = "xxxxxxxxxxxxxxxxxxxxxxxxxxx"
MQTT_PASSWORD  = "xxxxxxxxxxxxxxxxxxxxxxxxxxxx"
MQTT_CLIENT_ID = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxx"

client = cayenne.client.CayenneMQTTClient()
client.begin(MQTT_USERNAME, MQTT_PASSWORD, MQTT_CLIENT_ID, loglevel=logging.INFO, port=8883)
# For a secure connection use port 8883 when calling client.begin:
# client.begin(MQTT_USERNAME, MQTT_PASSWORD, MQTT_CLIENT_ID, port=8883, loglevel=logging.INFO)

i=0
timestamp = 0

DEBUG = 0
CMD_MODE = 2
CMD_QUERY_DATA = 4
CMD_DEVICE_ID = 5
CMD_SLEEP = 6
CMD_FIRMWARE = 7
CMD_WORKING_PERIOD = 8
MODE_ACTIVE = 0
MODE_QUERY = 1
PERIOD_CONTINUOUS = 0

JSON_FILE = '/var/www/html/aqi.json'

MQTT_HOST = ''
MQTT_TOPIC = '/weather/particulatematter'

ser = serial.Serial()
ser.port = "/dev/ttyUSB0"
ser.baudrate = 9600

ser.open()
ser.flushInput()

byte, data = 0, ""

def dump(d, prefix=''):
    print(prefix + ' '.join(x.encode('hex') for x in d))

def construct_command(cmd, data=[]):
    assert len(data) <= 12
    data += [0,]*(12-len(data))
    checksum = (sum(data)+cmd-2)%256
    ret = "\xaa\xb4" + chr(cmd)
    ret += ''.join(chr(x) for x in data)
    ret += "\xff\xff" + chr(checksum) + "\xab"

    if DEBUG:
        dump(ret, '> ')
    return ret

def process_data(d):
    r = struct.unpack('<HHxxBB', d[2:])
    pm25 = r[0]/10.0
    pm10 = r[1]/10.0
    checksum = sum(ord(v) for v in d[2:8])%256
    return [pm25, pm10]
    #print("PM 2.5: {} μg/m^3  PM 10: {} μg/m^3 CRC={}".format(pm25, pm10, "OK" if (checksum==r[2] and r[3]==0xab) else "NOK"))

def process_version(d):
    r = struct.unpack('<BBBHBB', d[3:])
    checksum = sum(ord(v) for v in d[2:8])%256
    print("Y: {}, M: {}, D: {}, ID: {}, CRC={}".format(r[0], r[1], r[2], hex(r[3]), "OK" if (checksum==r[4] and r[5]==0xab) else "NOK"))

def read_response():
    byte = 0
    while byte != "\xaa":
        byte = ser.read(size=1)

    d = ser.read(size=9)

    if DEBUG:
        dump(d, '< ')
    return byte + d

def cmd_set_mode(mode=MODE_QUERY):
    ser.write(construct_command(CMD_MODE, [0x1, mode]))
    read_response()

def cmd_query_data():
    ser.write(construct_command(CMD_QUERY_DATA))
    d = read_response()
    values = []
    if d[1] == "\xc0":
        values = process_data(d)
    return values

def cmd_set_sleep(sleep):
    mode = 0 if sleep else 1
    ser.write(construct_command(CMD_SLEEP, [0x1, mode]))
    read_response()

def cmd_set_working_period(period):
    ser.write(construct_command(CMD_WORKING_PERIOD, [0x1, period]))
    read_response()

def cmd_firmware_ver():
    ser.write(construct_command(CMD_FIRMWARE))
    d = read_response()
    process_version(d)

def cmd_set_id(id):
    id_h = (id>>8) % 256
    id_l = id % 256
    ser.write(construct_command(CMD_DEVICE_ID, [0]*10+[id_l, id_h]))
    read_response()

def pub_mqtt(jsonrow):
    cmd = ['mosquitto_pub', '-h', MQTT_HOST, '-t', MQTT_TOPIC, '-s']
    print('Publishing using:', cmd)
    with subprocess.Popen(cmd, shell=False, bufsize=0, stdin=subprocess.PIPE).stdin as f:
        json.dump(jsonrow, f)


cmd_set_sleep(0)
cmd_firmware_ver()
cmd_set_working_period(PERIOD_CONTINUOUS)
cmd_set_mode(MODE_QUERY);
while True:
    client.loop()
    if (time.time() > timestamp + 62):
        cmd_set_sleep(0)
        for t in range(15):
            values = cmd_query_data();
            if values is not None and len(values) == 2:
                print("PM2.5: ", values[0], ", PM10: ", values[1])
                time.sleep(2)
    
        client.virtualWrite(0, values[0])
        client.virtualWrite(1, values[1])

        print("Going to sleep for 1 min...")
        cmd_set_sleep(1)
        timestamp = time.time()

My code for BME680:

#!/usr/bin/env python
import cayenne.client
import time
import bme680
import logging

time.sleep(30) #Sleep to allow wireless to connect before starting MQTT

print("""read-all.py - Displays temperature, pressure, humidity, and gas.

Press Ctrl+C to exit!

""")

try:
    sensor = bme680.BME680(bme680.I2C_ADDR_PRIMARY)
except IOError:
    sensor = bme680.BME680(bme680.I2C_ADDR_SECONDARY)

# These calibration data can safely be commented
# out, if desired.

print('Calibration data:')
for name in dir(sensor.calibration_data):

    if not name.startswith('_'):
        value = getattr(sensor.calibration_data, name)

        if isinstance(value, int):
            print('{}: {}'.format(name, value))

# These oversampling settings can be tweaked to
# change the balance between accuracy and noise in
# the data.

sensor.set_humidity_oversample(bme680.OS_2X)
sensor.set_pressure_oversample(bme680.OS_4X)
sensor.set_temperature_oversample(bme680.OS_8X)
sensor.set_filter(bme680.FILTER_SIZE_3)
sensor.set_gas_status(bme680.ENABLE_GAS_MEAS)

# Cayenne authentication info. This should be obtained from the Cayenne Dashboard.
MQTT_USERNAME  = "xxxxxxxxxxxxxxxxxxxxxxxxx"
MQTT_PASSWORD  = "xxxxxxxxxxxxxxxxxxxxxxxxx"
MQTT_CLIENT_ID = "xxxxxxxxxxxxxxxxxxxxxxxxxx"


client = cayenne.client.CayenneMQTTClient()
client.begin(MQTT_USERNAME, MQTT_PASSWORD, MQTT_CLIENT_ID, loglevel=logging.INFO, port=8883)
# For a secure connection use port 8883 when calling client.begin:
# client.begin(MQTT_USERNAME, MQTT_PASSWORD, MQTT_CLIENT_ID, port=8883, loglevel=logging.INFO)

i=0
timestamp = 0

print('\n\nInitial reading:')
for name in dir(sensor.data):
    value = getattr(sensor.data, name)

    if not name.startswith('_'):
        print('{}: {}'.format(name, value))

sensor.set_gas_heater_temperature(320)
sensor.set_gas_heater_duration(150)
sensor.select_gas_heater_profile(0)

# Up to 10 heater profiles can be configured, each
# with their own temperature and duration.
# sensor.set_gas_heater_profile(200, 150, nb_profile=1)
# sensor.select_gas_heater_profile(1)

print('\n\nPolling:')
try:
    while True:
        client.loop()
        if sensor.get_sensor_data():
            output = '{0:.2f} C,{1:.2f} hPa,{2:.2f} %RH'.format(
                sensor.data.temperature,
                sensor.data.pressure,
                sensor.data.humidity)

            if sensor.data.heat_stable:
                print('{0},{1} Ohms'.format(
                    output,
                    sensor.data.gas_resistance))

            else:
                print(output)
                
        if (time.time() > timestamp + 10):
            client.celsiusWrite(1, sensor.data.temperature)
            client.hectoPascalWrite(2, sensor.data.pressure)
            client.virtualWrite(3, sensor.data.humidity,"rel_hum","p")
            client.virtualWrite(4, sensor.data.gas_resistance, "co","ohms")
            timestamp = time.time()
    
        time.sleep(1)

except KeyboardInterrupt:
    pass




while True:
    client.loop()
    
    if (time.time() > timestamp + 10):
        client.celsiusWrite(1, i)
        client.luxWrite(2, i*10)
        client.hectoPascalWrite(3, i+800)
        timestamp = time.time()
        i = i+1

Regards Przemek

Your code will be substantially different with Blynk but definitely doable. Use the sketch builder and do a couple of different examples. Once you get familiar it will be easier. Just a word of warning :warning: the Pi isn’t well documented and discussed on here. You’ll find your 32 the winner. Maybe use the Pi for your local server.

Hi, thanks for answers. I will experiment with my code then.
Regards Przemek.