Bad argument to select list item - in need of help

Mms · May 11, 2023, 8:45am

Hello everyone, hope everyone is doing well.

I'm currently working on a project and I've encountered an error that I'm having trouble resolving. Specifically, I'm trying to use the 'select list item' block to select an item from a list, but I'm having trouble passing the necessary arguments. Why is the bad arguments to select list error appearing here and how can I fix this problem?

I would greatly appreciate any help or suggestions that you might have. Thank you in advance for your time and expertise!

Kevinkun · May 11, 2023, 10:48am

Check all the 'SELECT LIST ITEM' blocks, make sure the list socket get a LIST WITH LENGTH >=1

ABG · May 11, 2023, 10:56am

Only read Bluetooth text once per Clock timer event, into a global variable.

Work on that variable from then on.

ABG · May 11, 2023, 10:56am

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.
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.

Mms · May 18, 2023, 1:49pm

Thank you ABG and I apologize for the late reply,
I set the delimiter of the Bluetooth client to 10 to recognize the end of line when receiving the data from Arduino UNO using println() but I forgot to include that point in my question, the error still appears. The arduino code just sends 3 FSR values and 3 angle values using println() and the values appear on the application ( I checked by making them appear in a textbox).

The error occurs during the calibration process (when calibration button is pressed) so I thought there is something I am doing wrong for TINYDB or the way I am getting the 6 values the code I used is attached below, is there something missing I should add in the code to fix this problem?
simplify_try.ino (1.4 KB)

ABG · May 18, 2023, 1:58pm

The way you send your 6 values makes it very hard to identify which is which on the receiving end (which you did not show).


 Serial.println(fr ); 
 
 Serial.println(fl ); 
 
 Serial.println(fc ); 
 Serial.println(x); 
 Serial.println(y); 
 Serial.println(z);
  
 delay(2000);

Figure out a way to either label the numbers ( print("x:"); println(x)) or
print all 6 numbers separated with commas or '|' on a single line.

Then adjust your AI2 end to watch for your markup and pick out the numbers.
Sample code for the receiving end:

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