Blynk not turning the LED ON on NodeMCU

[PeteKnight]

Okay, simple solution is to use the Python GUI to send an API call to a Blynk virtual pin - the same one that your Blynk on/off button is attached to.

You then have the code in your sketch that will turn the LED on and off according to the state of the virtual pin, as described 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…

The API documentation is here:

blynkapi · Apiary

I’d recommend using the GET method for everything.

However, if you’re building a serious IoT home automation system then I’d suggest a different approach, which is to use Node-Red and MQTT plus the Blynk plugin for Node-Red.

Pete.