Private IoT with Blynk on Local Server

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.

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

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 .

Configure the Server

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

Blink provides a procedure for the Raspberry Pi but it works for the BeagleBone.

On the BeagleBone,

First install Java 8 following this procedure

Second, create a Blynk folder and install the Blynk server

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

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.

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.

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.

On the main computer,

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

Second, download the server.

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.

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

Note the client doesn't display any prompt.

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.

Some Common Issues with Local Server

Here are the solutions to two issues I faced with the Blynk server running on BeagleBone.

Blynk server launch fails if one port is already used by another process. In my case, Apache was using port 8080.

To solve this, create on the Blynk folder a file called server.properties and add the code on the right.

Connection to the admin page of the local Blynk local server in a fails.

The browsers refuse to connect. Firefox provides more information: The certificate is not trusted because it is self-signed and then asks to add an exception. If the browser suggests to add an exception, accept. Otherwise, generate a not self-signed certificate.

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 local server from the Blynk application not as easy as expected

Wrap-Up

Very interesting solution for private cloud
Highly recommended