List index to large

Hi all i am try to connect esp32 with mit app inventer app to send data from esp32 to the app and the conection and the code is work corectly but he givs me this when he try the data on the app

how i can.solved
I did this vedio

It would help if you post a picture of your blocks, or an .aia
Search this forum for help how to do this.

(Canned Reply: ABG- Export & Upload .aia)
Export your .aia file and upload it here.



This is my blocks

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:

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.


1 Like

I changed delimitreByte to 10
And changed my last print to println
But still not working with the same error
code send data
older_monitor (1).aia (22.3 KB)

You totally ignored the part about using the LF message Delimiter in the AI2 code.

Here is a stock sample for a different item delimiter.
It needs modification to fit your '|'

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

BlueTooth_delimiter_sample.aia(3.4 KB) global message


You changed Clock milliseconds to 10.
I don't see any place where you changed the BT Delimiter.

One of us needs glasses.

Sory i rechanged i will do the change and resind it to you

How about you test your code before sending it to any one?

I am sorry for my mostics but i am new in it he gives me this error now

andthis the aia i just changed the , to |
and in the clock1 timer add set text to my 3 varibale
And changed label to my varibal in initialize global(message_labels)to
Please i am doing good or sooo bad
Agan i am.sorrry
older_monitor (3).aia (23.1 KB)

If you are asking for help, I recommend you to make it as easy for others to be able to help you ...
You probably will get more feedback then...

which means in your case post a screenshot of your relevant blocks...

To download the aia file, upload it to App Inventor, open it, do some bug hunting for you, etc... this takes time, and most people will not do that...
Thank you.


Trying to push the limits! Snippets, Tutorials and Extensions from Pura Vida Apps by icon24 Taifun.

(Canned Reply: ABG - Download those blocks and post them here)

Please download and post each of those event block(s)/procedures here ...
P.S. These blocks can be dragged directly into your Blocks Editor workspace.

See Download Block Images for a demo.


Be sure your Companion is up to date, too.