Python to Arduino via Blynk

Need Help With My Project
1

Hi!

I am trying to export an output integer (that continuously changes) from a Python script to my Arduino script so it can be used in a calculation running on the Arduino and the result later outputted to Blynk.
I am unable to use a serial connection for a direct transfer from Python to Arduino as I am already using a USB serial connection to connect my Arduino to Blynk.
I therefore have been trying to use the Blynk Python library to send the value from Python to a Blynk virtual pin in the hope that the Arduino can then retrieve this value via its Blynk connection.
While the correct value from Python shows on the Blynk app when I add a input field assigned to the virtual pin, I am however unable to get my Arduino code to retrieve the value. I have trued using the BLYNK_WRITE function, however it seems that this function only triggers when the virtual pin value is updated from an app widget (e.g. movement of a slider), and does not trigger when the value on the virtual pin itself (from Python) changes? Would really appreciate any suggestions please :slight_smile:

2

Are you using the same Auth code on both devices?
If yes, then you shouldn’t be.
You need different Auth codes and some Bridge code to get it working.

Pete.

3

Hi Pete, Thanks for the reply.
I’m using different auth codes already. For the bridge code I could only see examples for bridge code on Arduino and not for a Python script?

4

Not sure, I’ve never used Python.
What device are you running Python on?

Pete.

5

Not using a microcontroller device for Python just a PC which is running a machine vision algorithm on a live rtsp stream and outputting the variable on whether a person is present or not