Getting Runtime Error when trying to use Serial to communicate to Arduino

Sorry, tested 2022-04-13 and 2022-02-26. They all show the same error.

BTW, sending a text message (SMS) generates the same error.

This still is not working today (2022/10/27). Can anyone help to solve this problem?
Many thanks!

What is not working?

Dear Sir:
It shows runtime error. Would you please help me solve this promblem? Many thanks!

This works for me on Android 9:

There is a small change in the latest version (debug 22-10-19), so it should work with all versions of Android incl. Android12. I don’t have access to an Android12 device, so I really want to hear that it’s working with Android12.

Dear Sir,
Wound you please do the same thing for potencimetro.aia? Or Tell us how can we fix it by ourself. Many thanks!

Im having the exact same error except im on android 13 on a google phone, does anyone know how to fix it?

Dear Sir:
Many thanks for your help. The updated version is working! However, I still have problems drawing the line. Would you please help me with this problem?
Really appreciated!

For a better test on the incoming Y value, use the IS A NUMBER block.

Dear Sir:

Many thanks for your help. I used IS A NUMBER block. The APP seems to receive two sending data at one time. The Timer interval(10ms) is half of the sending interval(20ms). Any suggestions

Really appreciated!!

Don't use an AND block for your tests.
Nest the < comparison inside the IS A NUMBER test to prevent it from running if not a number.

Actually, you could use the and block here since it is lazily evaluated left to right. The problem is that the checks need to be ordered such that the is a number? check comes first so if it fails the rest of the code won't run (which the above code doesn't do).

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Hi !
I still have this issue with an application using the serial OTG component with Arduino.
What is the result of your investigation into the Physicaloid library ?
I've been looking for a while for an update...Is there any available ?

Are you using the Serial component or the SerialOTG extension? I cannot speak for the extension, but there is an update for the Serial component in process to address the Android 12+ issues. You can try out the test server at

Thanks for answering !
Yes i'm using the serialOTG extension.
FYI the code is working with the AI companion 2.64. But i have the run
time error with version 2.65

And it never works with the .apk build (on the test server also).
IHM_208.aia (231.6 KB)

An idea when the update addressing the Android 12+ issues will be released ?

Unfortunately I can't assist with the OTG extension since it's not published by MIT. @rkl099 may want to have a look though.

As discussed in Using serial with FTDI - #117 by rkuba
the SerialOTG version in GitHub - rkl099/Appinventor_Debug: Debug versions: SerialOTG, Modbus and test programs (Note: can be changed any time). has been updated so it should work with Android12 and has been tested by some users, as I don't have access to an Android12 device.
Your error code is probably from your block code and not from the extension.
It seems that you do a Read in your timer function without testing if you have received something. Read is a nowait function and returns an empty string or all character that have been received since last call. See Appinventor-SerialOTG/SerialOTG_1.4.pdf about Read and discussion about message handling.

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The extension works on Android12 on the normal server. Test server is not necessary.