# How to send value to thunkable x app via ble using a rn4020

**URL:** <https://community.thunkable.com/t/how-to-send-value-to-thunkable-x-app-via-ble-using-a-rn4020/441715>\
**Category:** Questions about Thunkable X\
**Tags:** bluetooth\
**Created:** [February 3, 2020, 4:05am UTC](https://community.thunkable.com/t/how-to-send-value-to-thunkable-x-app-via-ble-using-a-rn4020/441715 "2020-02-03T04:05:01Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![domhnallohanlon](https://sea1.discourse-cdn.com/flex015/user_avatar/community.thunkable.com/domhnallohanlon/32/29554_2.png) [@domhnallohanlon](https://community.thunkable.com/u/domhnallohanlon)\
**Post date:** [March 30, 2020, 3:34pm UTC](https://community.thunkable.com/t/how-to-send-value-to-thunkable-x-app-via-ble-using-a-rn4020/441715/2 "2020-03-30T15:34:28Z")

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Hey @H_i_CH_n_Nguy_n

You can try something like light blue to give you all the details about your BLE device(s)

> [@BLE Characteristic UUID issues](http://community.thunkable.com/t/ble-characteristic-uuid-issues/508037):
>
> I created an app: [Thunkable](https://x.thunkable.com/projects/5e447690fa2000a7c8ab5c14/420a269b-5845-4bc4-8fcb-4fa88a3e5e79/blocks) This app is using BLE to talk to an HM-10 module on arduino. When I scan, I find my device. When I connect, it reports that it is connected. When I try to send a string I get the error: “Can’t write the characteristic provided”. I attached screen shots of my block, lightblue screen shot, error message. I used lightblue to find the Advertised Service UUIDs. Is that the correct ID?[SurfBleBlock]

Hope that helps!

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