# Speed & Cadence Sensor Connection
**URL:** https://community.thunkable.com/t/speed-cadence-sensor-connection/1895086
**Category:** BLE / BlueTooth
**Created:** [May 25, 2022, 2:04pm UTC](https://community.thunkable.com/t/speed-cadence-sensor-connection/1895086 "2022-05-25T14:04:06Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@roykfv](https://community.thunkable.com/u/roykfv)
#### Post date: [May 25, 2022, 2:04pm UTC](https://community.thunkable.com/t/speed-cadence-sensor-connection/1895086/1 "2022-05-25T14:04:06Z")
Hi All, I try to connect a Speed & Cadence Sensor with UUID “00002A5B-0000-1000-8000-00805F9B34FB” all I get is a “Operation Rejected”
I can connect to the sensor and try to receive byte array but get “Operation Rejected” do I something wrong or is this not possible with Thunkable? I have this working in Unity3D but like to build it with Thunkable.
Thx! Roy
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### Author:  [@jared](https://community.thunkable.com/u/jared)
#### Post date: [May 25, 2022, 2:59pm UTC](https://community.thunkable.com/t/speed-cadence-sensor-connection/1895086/2 "2022-05-25T14:59:34Z")
are you connecting to the device first? The image below is how I connect. to one of my own BLE devices.
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### Author:  [@muneer](https://community.thunkable.com/u/muneer)
#### Post date: [May 25, 2022, 3:26pm UTC](https://community.thunkable.com/t/speed-cadence-sensor-connection/1895086/3 "2022-05-25T15:26:10Z")
This will not work. Your device has only **NOTIFY** property in this UUID and you are trying to do a **READ** operation. So `Operation Failed` is a logical response. You need the **READ** property to do this.
Currently Thunkable does not listen to **NOTIFY** channels.
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### Author:  [@roykfv](https://community.thunkable.com/u/roykfv)
#### Post date: [May 27, 2022, 7:22am UTC](https://community.thunkable.com/t/speed-cadence-sensor-connection/1895086/4 "2022-05-27T07:22:30Z")
Hi Muneer, Thanks for your answer. Notification doesn’t need to be acknowledged, so they are faster and an efficient way to read data continuously, Hope this will be supported but think this will be a long wait.
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### Author:  [@muneer](https://community.thunkable.com/u/muneer)
#### Post date: [May 27, 2022, 7:38am UTC](https://community.thunkable.com/t/speed-cadence-sensor-connection/1895086/5 "2022-05-27T07:38:28Z")
> [@roykfv](#):
>
> Hope this will be supported
I hope so.
In the classic `Bluetooth` connection, `Read & Write` can only take place after connecting (pairing) with the Bluetooth device. But this has a downside because Bluetooth devices allow only one single `pairing` at any one time.
The answer was with **BLE** notification which does not require `pairing` but rather `Subscribing` to the service.
Let’s hope Thunkable will introduce `subscription` to **BLE** devices (services).
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### Author:  [@yurgen](https://community.thunkable.com/u/yurgen)
#### Post date: [December 1, 2022, 10:38pm UTC](https://community.thunkable.com/t/speed-cadence-sensor-connection/1895086/6 "2022-12-01T22:38:59Z")
Does anyone know about update of this?
Its a highly requested functionality.
I dont understand why in Thunkable BLE only can work with Read Characteristic but it can not Subscribe to Notify Characteristic.
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### Author:  [@ioannis](https://community.thunkable.com/u/ioannis)
#### Post date: [November 8, 2024, 1:13pm UTC](https://community.thunkable.com/t/speed-cadence-sensor-connection/1895086/7 "2024-11-08T13:13:14Z")
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### Author:  [@matt\_conroy](https://community.thunkable.com/u/matt_conroy)
#### Post date: [December 19, 2024, 5:00pm UTC](https://community.thunkable.com/t/speed-cadence-sensor-connection/1895086/8 "2024-12-19T17:00:12Z")