NodeMCU with Blynk goes offline and back online as frequent as 10 seconds

[PeteKnight]

When you look at the data in your serial monitor, is the device rebooting when it goes offline in Blynk?

If you change this line:

@DTalisman

Serial.begin(9600);

to either 74880 or 115200 (it depends on your board, but usually 74880 will work) and set the serial monitor to the same baud rate, you will see boot messages from the board as well as the debug messages from Blynk.
If your board is rebooting then you’ll see a reason code, which will tell you why it’s rebooting.

@DTalisman

I created all four streams to be digital and not virtual pins (virtual didn’t work out)

I’ve never been a fan of digital datastreams, especially the way that they’ve been implemented in Blynk IoT. You’d be far better using virtual pins. More info here…

Using Virtual Pins to control physical devices

I thought I’d write a guide about how to use virtual pins with app widgets such as buttons, to control physical devices such as relays, LEDs etc… Why use virtual pins anyway? I’d always recommend using virtual pins over physical pins when developing your code. There are a number of reasons, but here are what I consider to be the main ones: Virtual pins are hardware independent. This means that it’s far easier to port your code from one hardware platform to another in future (when you realise…

@DTalisman

Do you recommend I use a voltage higher than 5?

No! the NodeMCU needs 5v via the USB connector. It’s more about the current that the power supply can deliver, and whether or not the power is ripple-free. Also, you could have a problem with your USB cable, so try a different one.

Pete.