Best Smartphone for Bluetooth Blynk Communication

Dear Forum,

I am currently using the Blynk app on an LG Aristo smartphone and communicating with an Arduino Pro Mini (3.3V) using an HC-06 Bluetooth module. This works GREAT!!!

I gave my friend the physical circuit with the Arduino Pro Mini connected to the HC-06 Bluetooth module. I provided him with shared access to the Blynk app. I toggled shared access to “ON” and then clicked on “Generate Link”. I e-mailed the link and QR code to him.

My friend is not able to establish and/or maintain the Bluetooth connection with the device for more that 1-2 seconds. He has tried a couple of different Android smartphones including a Cricket smartphone and a Motorola smartphone…not sure which models.

Can anybody suggest the BEST smartphone(s) for connecting to the HC-06 Bluetooth Module and used with the Blynk app? (in addition to the LG Aristo)


I don’t use Bluetooth with Blynk, but personally I just can’t get my head around the concept of shared access to a Bluetooth device in the way you’ve described.

Normally, with a Wi-Fi or Ethernet connected device, the communication route is that the device talks to the Blynk server across an internet connection, and the mobile device (phone/tablet) also talks to the Blynk server across an internet connection.
For the sake of this discussion, let’s say that the devices are located in your home.
When you share this project, the people you share this with have access to see the data that comes from the devices that are located in your home, and control them - regardless of where they are themselves.
The sharing process is there to give other people (and this is generally non-technical members of your household) the ability to control these Blynk connected devices without also giving those people the ability to edit the app project settings. That privilege is reserved for you as the account owner.

With Bluetooth, the connection is local because of the nature of the communication method, and the phone/tablet can act as a bridge between the Bluetooth device and the Blynk server (although I think this is optional, depending on whether an internet service is available and whether the direct connect option is used - I think).
When you share a Bluetooth project, I can’t see how the Bluetooth device(s) located in your home can be operated by the shared user, unless your phone is connected to that device.
What you’ve described is something very different, and it seems to me that what was actually needed was a clone of the project, and the Bluetooth device running a sketch with a different Auth code rather than the same one that your device uses.


Dear Pete,

Thank you for your reply.

I am not quite sure which scenario is correct.

If I gave my friend the device and then shared the link with him, then shouldn’t he be able to run the device on his smartphone with the shared link and from his WiFi network? I was able to operate the circuit from a different WiFi network from the “originating” Android smartphone. So shouldn’t my friend be able to use the shared link to run the device from his WiFi network?


I don’t understand where the WiFi network of this statement comes in to play, or why sharing is involved.
Also, if WiFi is available then why are you using Bluetooth?


Dear Pete,

I misunderstood your original comment. I thought that you were suggesting that WiFi had something to do with this. My mistake.

The device that I created is a Bluetooth controlled motor. I use a smartphone running the Blynk App to control the motor (on/off, speed, pulses, etc…).

The question is really which smartphone(s) running the Blynk App can pair to an HC-06 Bluetooth module?


Okay, I’ll respond once more then leave you to figure it out yourself.

I don’t believe that the connection issues your friend is experiencing is because of the type of smartphone that he is using, I believe that it’s because you are using a shared Blynk project.

I may be entirely wrong, but if you re-read my rather long explanation about why I think this is the case them maybe you’ll see why I think this.


Dear Pete,

I now understand what shared access dictates. If I grant “shared access”, the Blynk app MUST be running on the original smartphone (#1) simultaneously with the Blynk app running on the other smartphone (#2). Every keystroke on smartphone #1 is mirrored on smartphone #2. This is NOT what I was looking for.

I then discovered that at the very bottom left corner of the screen on smartphone #1 where you can provide shared access, there is a button to “Clone” the app. This IS what I want. So I made sure that the “shared access” copy of the Blynk app on smartphone #2 was deleted from the second smartphone, and I “Cloned” the app from smartphone #1. I generated the clone QR code on smartphone #1 and then scanned the QR code with the smartphone #2. Now I have 2 independent copies of the app that can both connect to the physical hardware.

I powered down smartphone #2 and tried running the app from the original smartphone #1.

I get 2 errors:

  1. wasn’t online yet
  2. Bluetooth - Can’t connect. Something went wrong when connecting to your Bluetooth device. Please try again later.

I checked the authorization code for smartphone #1 to confirm that this has not changed. It may have changed for smartphone #2 with the cloned copy. I have not yet verified this. And I have powered down smartphone #2.

At the end of the day, the app no longer works. Nothing changed on smartphone #1. The app hasn’t changed, the C code on the Arduino hasn’t changed…nothing changed. Can you please suggest possible causes?

By the way, both smartphone #1 and #2 see the HC-06 Bluetooth module. The HC-06 shows up o the list of Bluetooth devices. I am able to pair between either of the smartphones and HC-06, but they just cannot connect from within the Blynk app. The wired providing power, gnd, rx, and tx are soldered from the Arduino Pro Mini to the HC-06 and none of the wires have broken loose. Everything is still perfectly connected.


No, you have two independent copies of the app that can run on DIFFERENT physical hardware.

Cloning is a way of allowing someone to re-create the setup of the app, without having to do it manually. The user who imports this cloned copy of the app into their own Blynk account will have a different auth token, which they will put into the sketch and upload to their own hardware, giving them the same user interface in that app as you originally designed, but using it to control their own hardware.

The solution is to stop using Bluetooth if you want to give more than one person access to your physical hardware.


Dear Pete,

I only have one assembly of hardware (not multiple), and I am giving the hardware to person #2 to control with smartphone #2. So I will no longer be able to control the device from smartphone #1.

So I apologize if I did not articulate that correctly in my last post.

In doing so, I will generate a new auth code and re-flash the microcontroller.

I also now believe that I had a brownout issue with the microcontroller. I have authored a post on the Arduino forum about modifying fuses as I am not quite sure how to do this. I have done some research and waiting on a few pointers from the Arduino forum.

Thank you for your feedback.