App crashes, maybe because of simoultaneous clocks and bluetooth?

Hello! I've been working on this project for some time (it is my first) and right when I thought I had everything and just needed to put it all together, I can't get my app to not crush when I hit play for the first exercise :frowning:

In summary, the app is supposed to start a count of the resps/seconds for each exercise and simultaneouly read the sensors from arduino depending on the type of exercise. When I start the first exercise, it crashes right away. When I don't start the clock used for the bluetooth, it works fine (but obviously doesn't read the sensors' data).

Anyone have any idea of why this happens? And if so, do you think I can work around it?

Thank you so much.

(Attached is the inventor app and the code I'm using)
need_help.aia (2.3 MB)

code_app_mit_inventor.ino (2.7 KB)

I don't see you setting up bluetooth permission in screen4.

(Canned Response)
These blocks can be dragged into your Blocks Editor to request permission(s) for Bluetooth scanning and connecting. All three parts are needed.

Thanks to @Anke for the original code.
My changes include

  • use of the Screen1 permission blocks to avoid the possibility of a typo
  • using a TinyDB tag particular to BT permissions and only for BT permissions.

I also do not see you receiving BlueTooth text in a standard manner using Delimiters.
Here is the standard advice for that:

Please see the Delimiter article in FAQ

Be sure to use println() at the end of each message to send from the sending device, to signal end of message. Do not rely on timing for this, which is unreliable.

In the AI2 Designer, set the Delimiter attribute of the BlueTooth Client component to 10 to recognize the End of Line character.
Also, return data is not immediately available after sending a request,
you have to start a Clock Timer repeating and watch for its arrival in the Clock Timer event. The repeat rate of the Clock Timer should be faster than the transmission rate in the sending device, to not flood the AI2 buffers.

In your Clock Timer, you should check

  Is the BlueTooth Client still Connected?
  Is Bytes Available > 0?
     IF Bytes Available > 0 THEN
       set message var  to BT.ReceiveText(-1) 

This takes advantage of a special case in the ReceiveText block:

Receive text from the connected Bluetooth device. If numberOfBytes is less than 0, read until a delimiter byte value is received.

If you are sending multiple data values per message separated by | or comma, have your message split into a local or global variable for inspection before trying to select list items from it. Test if (length of list(split list result) >= expected list length) before doing any select list item operations, to avoid taking a long walk on a short pier. This bulletproofing is necessary in case your sending device sneaks in some commentary messages with the data values.

Here are some blocks for receiving text ...

Here is an updated blocks sample illustrating these ideas ...

BlueTooth_delimiter_sample.aia (3.4 KB) global message