# BLE Characteristic UUID issue for BatteryLevel

**URL:** https://community.thunkable.com/t/ble-characteristic-uuid-issue-for-batterylevel/3157751
**Category:** BLE / BlueTooth
**Tags:** solved
**Created:** [August 25, 2024, 9:26am UTC](https://community.thunkable.com/t/ble-characteristic-uuid-issue-for-batterylevel/3157751 "2024-08-25T09:26:13Z")
**Posts on this page:** 4
**Page:** 1

<div class="post-metadata">

### Author: ![didier.coymanohatdl](https://avatars.discourse-cdn.com/v4/letter/d/c89c15/32.png) [@didier.coymanohatdl](https://community.thunkable.com/u/didier.coymanohatdl)
#### Post date: [August 25, 2024, 9:26am UTC](https://community.thunkable.com/t/ble-characteristic-uuid-issue-for-batterylevel/3157751/1 "2024-08-25T09:26:13Z")

</div>

I am using an ESP32 to publish some telemetry. Using the GATT specification, I try to connect to the characteristic UUID 2A19 published by the ESP32 without success. I get a “Can’t read characteristic provided.” I can see it and I can read it using the RF Connect app. As per the bluetooth specification the characteristic is READ, NOTIFY.  
I tried the connect to 2A19 or 00000000-0000-0000-0000-000000002A19, no difference.

Connecting to a generated UUID and read other characteristics works fine. Any idea why the official UUID for BatteryLevel can’t be read?

---

<div class="post-metadata">

### Author: ![didier.coymanohatdl](https://avatars.discourse-cdn.com/v4/letter/d/c89c15/32.png) [@didier.coymanohatdl](https://community.thunkable.com/u/didier.coymanohatdl)
#### Post date: [August 26, 2024, 10:53am UTC](https://community.thunkable.com/t/ble-characteristic-uuid-issue-for-batterylevel/3157751/2 "2024-08-26T10:53:27Z")

</div>

![image](https://us1.discourse-cdn.com/flex015/uploads/thunkable/original/3X/6/a/6a10a3d3e188461d3db7aff9a3f55314c9debc57.png)

---

<div class="post-metadata">

### Author: ![matt\_conroy](https://sea1.discourse-cdn.com/flex015/user_avatar/community.thunkable.com/matt_conroy/32/150843_2.png) [@matt\_conroy](https://community.thunkable.com/u/matt_conroy)
#### Post date: [August 26, 2024, 1:12pm UTC](https://community.thunkable.com/t/ble-characteristic-uuid-issue-for-batterylevel/3157751/3 "2024-08-26T13:12:25Z")

</div>

@didier.coymanohatdl If the documentation only gives four characters for the value, they are assuming you’ll use the default characterstic UUID.

It is discussed more in this previous topic.

> [@Trying to connect Bluetooth BP cuff, but struggling with the "characteristic UUID" stuff](https://community.thunkable.com/t/trying-to-connect-bluetooth-bp-cuff-but-struggling-with-the-characteristic-uuid-stuff/1849525/4):
>
> This is the default or base UUID for all characteristic IDs if not set by the factory. The default is 00000000-0000-1000-8000-00805F9B34FB If the manufacturer is giving you only 4 digit then it is assumed that you need to use the default UUID. It starts with 8 hexadecimal digits and you need to add your 4 digit hexadecimal number as the second part of it. So instead of all zeros it would be 0000 plus your code FFF4

---

<div class="post-metadata">

### Author: ![didier.coymanohatdl](https://avatars.discourse-cdn.com/v4/letter/d/c89c15/32.png) [@didier.coymanohatdl](https://community.thunkable.com/u/didier.coymanohatdl)
#### Post date: [August 26, 2024, 2:07pm UTC](https://community.thunkable.com/t/ble-characteristic-uuid-issue-for-batterylevel/3157751/4 "2024-08-26T14:07:34Z")

</div>

It did indeed fix the issue, Thank you so much.