BLE data every 5 ms

[Nico3]

Hello,

I designed my custom board using STM32WB series to be connected to sensor and send data to CLIENT which is my laptop.  I am able to use Write and Read Characteristics for a single character.

Now I intend to use READ characteristic to send data every 5 millisecond to laptop.  My sensor data payload can be maximum 120 Bytes.

Do you see any issues here on STM32WB ? Does BLE support this much ?

[Andrew Neil]

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@Nico3 wrote:

I intend to use READ characteristic to send data every 5 millisecond

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Does it really need to be that fast?

As well as the the STM32, you have to consider the PC end - it may not allow such fast updates...

[urbito]

I was wondering the same, i dont think Host PC can handle that rate. 

In the other hand, i am able to transfer up to 512 bytes per window using BLE. But i never tryed as a constant way to update but more like "when" some variable suffer a change in the "server" i make a "notifcation" to update that value in the paired client. At the end BLE is not like UART, in BLE you have characteristics and they should be used for particular scenarios.

[Andrew Neil]

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@urbito wrote:

I was wondering the same, i dont think Host PC can handle that rate. 

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It's not so much that it can't handle it - just that it may not allow it.

Windows decides how it allocates the radio resources.

Similarly on phones/tablets.

You didn't if it really needs to be that fast?

[Nico3]

I am data logging vibration data from multiple sensors. I need vibration data atleast of 10Hz frequency.  So I need to sample atleast at 20Hz.  That means data logging every 50 ms. 

I am thinking to go higher as much possible so data FFT is more reliable.  If 5ms is too much, then i go for 20 or last 50 ms. 

[urbito]

Arent you able to hold that data in host MCU for 500ms and then send it to Client PC? For example...

[Nico3]

yes,,this can be workable... never came to my mind.. 

[urbito]

Then try to give it a shoot :)

Hopefully it helps!

Greetings