Hi Ron.
Can you be a little more specific?
Depending on the data you want to send, and on your project, one method might be more suitable than the other.
Regards,
Sara

Normally it is very simple however it has stopped working for me. I have an Arduino sketch that transmits simple data “Hello RPi”. I test it and it is sending the text. At the Python program I use data = ser.readline(), etc.. Nothing is received and printed!
Don’t bother trying to analyze this. Must be a hardware problem but I have tried two Arduinos and two different Rasp Pi boards. IT USED TO WORK!! I will try again and try to come up with a more specific question. So just wait for a more specific question before answering. Thank you for responding.

Hi Ron.
Double-check the code you’re using. Sometimes we make small changes to the code without noticing and then, it stops working.
If it used to work, there must be a small change responsible for the problem, or maybe some sort of hardware problem.
Regards,
Sara

I finally found my problem. Selecting the “ttyAMAO” is the problem (I’m sending Arduino output to RasPi Python). For whatever reason, the system keeps changing the “tty–” device that will work. A few minutes later, if I have halted the program, the system again changes the allowable devices. Very frustrating! I need to learn more about why this happens.

Hi.
Unfortunately, I don’t know why that happens.
At least, now you know the source of the issue and you know what you should be looking for.
Regards,
Sara