I need help with my project. Below is my design app.
Upload the .ino sketch code here so we can see how the data is sent.
Also,
(Canned Reply: ABG- Export & Upload .aia)
Export your .aia file and upload it here.
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Be sure to use println() at the end of each message to send from the sending device, to signal end of message.
Only use print() in the middle of a message.
Be sure not to println() in the middle of a message, or you will break it into two short messages and mess up the item count after you split the message in AI2.
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:
ReceiveText(numberOfBytes)
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.
Some people send temperature and humidity in separate messages with distinctive prefixes like "t:" (for temperature) and "h:" (for humidity).
(That's YAML format.)
The AI2 Charts component can recognize these and graph them. See Bluetooth Client Polling Rate - #12 by ABG
To receive YAML format messages, test if the incoming message contains ':' . If true, split it at ':' into a list variable, and find the prefix in item 1 and the value in item 2.
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I can't check the result for now, so I will inform you soon if I have the program ready to see if there is a problem or not. But for now, is this alright for me to test and run?
TA (1).aia (727.4 KB)
Oh, to add more, I want to ask furthermore. I am using STM32 for this project, you said that I need to use println() and print() for sending the value. If I am using STM32, is there any difference that I need to put so the MIT App can recognize the item count?
I have not seen any sketch (.ino) code yet, so I can only guess.
I am pretty sure your blocks are wrong.
I'll tell you why after I see your sketch.
(Is this one of those project teams where one student does the sketch, and the other does the app, and they don't talk to each other?)
I am not using Arduino in this case, but STM32CubeIDE. And no, this is not a project team. I need to do a lot of things alone so I don't do everything step by step but in any order. 
I will come back later when I am done with the program.
I advise you not to mix data types in the same data stream.
Just use text
Do a single read into a variable in each clock cycle and deal with it.
