Hello,
we plan an Application for XDK which samples the Sensor BMI 160 (all 6 measurements) with 400 Hz.
The Data are send via Bluetooth Low Energie (BLE) to a Smart-Phone.
The maximum BLE Datarate is 1MBit/s. This should be enough.
But in Your 'Getting_Started.pdf' Chapter 4.1 on the DEMO Sensor Monitor Applikation, a 'constrait of communication channel on the XDK' is described. Therefore we can only get data every 100 ms (?).
Is it in principle possible, that the XDK can send BMI-160 Sensor date with 400 Hz via BLE ?
On the DEMO-Data Logger Appllication, we can also log mutch faster than every 100 ms.
Kind Regards
  Manfred


 
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Sending Sensor Data to a BLE Device with 400 Hz
Antwort
04.09.15 15:18 als Antwort auf Manfred Holzapfel.
Hello, 
I think, I should describe more detais of our problem:
We plan to sample the BMI-160 with 400 Hz, collect the sampled data in RAM for 10 seconds and then send it (e.G. as JSON-String wit the size of about 400 KB) via BLE. Then we pause for about 50 s.
Is this in principle possible on the XDK110 ?
Thanks for Your Help
Kind Regards
  Manfred
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Sending Sensor Data to a BLE Device with 400 Hz
Antwort
08.09.15 02:51 als Antwort auf Manfred Holzapfel.
Hi Manfred,

thanks for your question.
It's interesting to see what our Users intend to do with the XDK and we're more than happy to support them in their doing.


The DataLogger demo is limited by the way it's architectured and it's saving it's data to min 20ms sampling rate (for 6 sensors, min sampling = sensors x 2ms), so anything faster is not possible with the DataLogger demo.

In general though, what you intend to do should be no problem at all. That's what the XDK is actually designed for. The problem with the DataLogger demo that limits the sensors to 20ms and causes some of the known problems is caused by the I2C connection to the SD card and furthermore the way data is cached (or not cached). 

In short, your problem should be solveable. 

Keep us posted on how you're doing and more important, if you have any questions, feel free to ask. 
We're more than happy to support you on this.

- Florian
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Sending Sensor Data to a BLE Device with 400 Hz
Antwort
08.09.15 06:36 als Antwort auf Florian Harr.
Hi Florian,
thanks for Your Help.
I think, the constraint described in Chapter 4.1 of the 'Getting_Started.pdf' docoment for the  "XDK DEMO Sensor Monitor Applikation"

with the text

"4.1 Collection interval and sensor selection
Collection interval is limited by a constraint of communication channel on the XDK: data for each sensor (temperature, humidity and pressure are considered as one sensor) could not be collected in an interval smaller than 100ms. Per example, the minimum interval for 2 sensors is 200ms.
Sensor selection is constraint by the collection interval. A sensor could be added if the collection interval is set accordingly. "

is not relevant for us (?)

Kind Regards
  Manfred
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Sending Sensor Data to a BLE Device with 400 Hz
Antwort
12.09.15 03:16 als Antwort auf Manfred Holzapfel.
Manfred,

it should be relevant to you and in addition to that, this constraint is a Software limitation that should be fixable by Software, not by Hardware modifications.

I just wanted to point it out with the addition that this might not only be a problem with the SPI connection to the SD card, but with the Demo architecture in general.
My main concern to point this out was to make you aware of this and hopefully save you from hours of searching for a problem in case you were planning to reuse part of the Demos source codes.

Hope that answered your question.
Let me know how it goes or how we can help you.

- Florian
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Sending Sensor Data to a BLE Device with 400 Hz
Antwort
26.10.15 14:39 als Antwort auf Florian Harr.
Hi Manfred,

Did you get your solution working?

I have a similar question that i posted in a new thread before i found this one:
I would like to live stream data at 100 Hz or 200Hz via BT or Wifi from the XDK to a phone.

Do you have some suggestions of the quickest way to write a simple demo for this seeing as the demo code cannot be used here?

-Christine
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Sending Sensor Data to a BLE Device with 400 Hz
Antwort
27.10.15 07:39 als Antwort auf Christine Martindale.
Hi Christine,

ouer solution is already in planig.

- Manfred
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Sending Sensor Data to a BLE Device with 400 Hz
Antwort
27.10.15 08:13 als Antwort auf Manfred Holzapfel.
Hi Manfred,

Could you give me some suggestions or an example of the best way to go about a higher frequency using BT?

-Christine
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Sending Sensor Data to a BLE Device with 400 Hz
Antwort
27.10.15 13:18 als Antwort auf Christine Martindale.
Christine,

I'll responded to your original thread. 

Let's see that we can help you making this possible for you.

- Florian
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