Hm-10 BLE specific Firmware to connect with Blynk

Hi there blynkers,

During one month I’ve been trying to connect my Arduino Pro Micro with a BLE module (hc-8 and hm-10) and the BLE widget seems not to find the device.
Regardless of the code I’m uploading to the Arduino, (I assume) the BLE should be paired, first. To do so, I click on BLE Widget settings and “connect BLE device” but I could never have a connection there. Nothing happens.

Of course, when I clik on Play, a notification appears: “Device is offline”

I wonder if it is a matter of the firmware installed in the BLE module.

Thank you very much.

What type of phone, Android or IOS?

It is an Android Xiaomi 5

With BLE I don’t think you need to pair it first in the phone settings. However, yes you do need to connect it using the Widget.

When you open the BLE Widget and press ‘Connect BLE Device’ does it scan for and show your BLE Module?

Right, since it is a 4.0 Bluetooth, you don’t need to go to phone settings.
When I open the BLE Widget and press ‘Connect BLE Device’ It doesn’t show my BLE Module.

When you click on the little circle with arrow, to the right of the words ‘Select BLE device’, do you get the juggling green balls for a few seconds… then nothing?

Exact :slight_smile:

Unfortunately that means your phone either doesn’t recognise your BLE devices. Or, more likely and as you guessed, they are in need of proper firmware or internal setup. Blynk can only work with what the phone’s BT & BLE radio can detect.

Ok, you are absolutely right. I tried now with an iPhone 7 and now I can select the BLE module. The hm-10 BLE module appears as HMSoft.
Then, I select it and spend some time trying to connect.
Unfortunately, I receive a message that says “Can’t connect. Please retry or choose another device”

And last I recall… Blynk’s BLE Widget is not yet supported on IOS… Sorry, I think that is all I can help with.

Oh, I see.

But my Xiaomi can work well with these BLE modules since I already used them in other apps and applications.
So is not a problem of the phone.
I guess the only thing to try is the firmware thing.

Hmmm… if the phone does work, as evidenced in other BLE apps as you say… then perhaps the issue is the hardware model device that you are choosing in the Blynk app? What are you choosing? And while at it… what App version?


@Gunner Thanks a lot for your follow up of the case.

Seems that Xiaomi’s Miui Android version doesn’t gives the GPS permission to the app automatically. It is neccessary to go to settings, permissions, find the Blynk app and allow Gps location.

After that you can see all the bluetooth devices.


Maybe it is filtered out due to not supported UUIDs - we have a list of supported devices for BLE widget:

But it seems that your device should be supported. I’ll update later logging build in the thread concern by BLE issues: BLE connection problems / a question to all blynk users - if you have time you could use it and send me a log generated by the app, so I’ll check is this device filtered out from scan list.

Ou, I’ve missed your latest comment - yep, from Android 5.0 apps needs to have GPS permissions to be able to scan ble/wifi =(

Had Blynk app not notified you about this permission request?
In case you will face any issues with BLE support - please check the build mentioned by Gunner, from which you could send a log to me to investigate possible bugs with BLE support.