How do i fix data classification error?

hinpt19 · August 14, 2023, 1:49am

Im send data from the sensor to the app via Bluetooth, the blocks will classify the sensor's parameters with ”I” and continuously save it to TinyDB for processing and comparing data. After processing and comparing, I send a signal from the app to the main board to reset the sensor to process and compare the data for another time. However, when the sensor starts up, I have to use the calibration command to get the sensor's parameters to 0, when the sensor resets it will print non-parameter command lines and when they are sent to the app, the blocks cannot be sorted. Type them into TinyDB.
This my block get, classify dato and save to TinyDB:

This command line is printed after adjusting the sensor parameter:

and this error:

help me, please! thanks all.

ABG · August 14, 2023, 2:34am

You split the incoming data at '|', but you don't send any '|'.

After you do the split, you blindly assume there was a '|' when you try to select item 2 from the split result, because you did not test length of list and you did not check for any other text you send.

Further help is impossible without a full export of both sides of the code.

hinpt19 · August 14, 2023, 3:08am

thanks for rep, ABG:
Here is some more information, hope you can help
this my code
1m.ino (1.3 KB)

ABG · August 14, 2023, 10:34am

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.
BlueToothClient1_Properties
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.