Private IoT with Blynk on Local Server

Concerned about IoT privacy on the cloud? Blynk offers an interesting option for improved security with a local server.

Categories: Advanced

Originally published at https://www.hackster.io/rei-vilo/private-iot-with-blynk-on-local-server-619926.

Concerned about IoT privacy on the cloud? The 
Blynk
 solution offers an interesting option for improved security with a local server.

I tested it with the following configuration:


  • The LaunchPad TM4C123 programmed with Energia performs the
    data acquisition
    with the Grove BoosterPack and the same sensors as in the
    Weather and Security Station with Blynk
    . Connection to the server is done through WiFi with the CC3100 WiFi BoosterPack.

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  • A BeagleBone White running on Debian hosts the
    server
    , with Blynk server release 0.8.0,

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  • The Blynk version 1.0 RC7 for Android
    displays
    the data on a Slate 7 Plus tablet from Hewlett Packard running on Android 4.2.2 .

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Prepare the Hardware

As for the project
Weather and Security Station with Blynk


, the hardware includes a LaunchPad CC3200 and a Grove BoosterPack with 4 elements:

  • a PIR detector (input pin 27),
  • a DHT22 temperature and humidity sensor (input pin 24),
  • a BMP180 pressure sensor (I²C port) and
  • a relay (output pin 23).

The Grove system makes connections very easy. Just plug and play!

Plug and play!

Configure the Server

The server is hosted in a BeagleBone, connected through Ethernet to a WiFi router. 




$
java -version
java version "1.8.0_60"
Java(TM) SE Runtime Environment (build 1.8.0_60-b27)
Java HotSpot(TM) 64-Bit Server VM (build 25.60-b23, mixed mode)

  • First install Java 8 following this 
    procedure

# apt-get install oracle-java8-installer

  • Second, create a Blynk folder and install the Blynk server

# mkdir ~/Blynk# wget https://github.com/blynkkk/blynk-server/releases/download/v0.8.0/server-0.8.0.jar

  • Third and finally, launch the server and note the IP address of the BeagleBone.



# cd ~/Blynk
# java -jar server-0.8.0.jar -dataFolder ~/Blynk &

Open the Blynk Application

Connecting the Blynk application to the server was the tricky part. I wasn’t able to connect to the server directly from the application. d>

The procedure should have been:

  • On the main screen, select the server to connect to.
  • On the Server Settings, select
    Custom
    and enter the IP Address of the server.
  • Press
    OK
    to return to the main screen.
  • Press
    Create Account
    and enter the credentials. 

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The credentials consist on an e-mail address with a 
@ 
and a . like in name@mail.com, and a non-empty password. Both are compulsory. Otherwise, the app displays a cryptic message.This last part didn’t work for me. I reported the bug and Blynk is working on an fix. 

As an option, Blynk provides a 
client to emulate a smartphone
, with handy commands to create and configure a client.

  • First, check Java 8 is installed. If required, download and install it.




$
java -version
java version "1.8.0_60"
Java(TM) SE Runtime Environment (build 1.8.0_60-b27)
Java HotSpot(TM) 64-Bit Server VM (build 25.60-b23, mixed mode)

  • Second, download the client.

$ wget https://github.com/blynkkk/blynk-server/releases/download/v0.8.0/client-0.8.0.jar

  • Third, launch the client.  192.168.1.26 is the IP address of the BeagleBone and 8443 is the default port of the Blynk server.

$ /usr/bin/java -jar client-0.8.0.jar -mode app -host 192.168.1.26 -port 8443

  • Finally, create the user, a dashboard and note the authentication string, like "1a2b3c4d5e6f7g8h9i0j1k2l3m4n5o6p".



register name@mail.com password
login name@mail.com password
saveProfile {"dashBoards":[{"id":1, "name":"Local Weather", "boardType":"LaunchPad CC3200"}]}
getToken 1
activate 1

Back to the tablet, 


  • Launch the Blynk application and select
    Log In
    .
  • Proceed as before for selecting the server and entering the IP address of the BeagleBone.

  • Type in the credentials name@mail.com and password, and press the 
    Log In
    button.
  • Blynk grants access and shows the empty dashboard previously created with the client.

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Adapt the Sketch

Just edit the 
Blynk.begin() 
and add the IP address of the server.

Conclusion

The Blynk sever offers many 
more options
, as 
e-mail
, debug log level, number of users, 
data storage
, 
SSL certificates
. Contrary to other options like 
Phant used by Sparkfun Data
, there’s no need to stop Apache.

The only difficult part was the configuration process, which is being fixed. The forum was of great help on solving this issue.

The Blynk server offers a very interesting solution for private cloud, from start to finish.

  • Pros: 
    Private cloud, 
    Data retention
  • Cons: 
    Connection to the server from the Blynk application not as easy as expected
  • Wrap-Up: 
    Very interesting solution for private cloud, 
    Highly recommended

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