Level output and relay

I have a problem with blynk and Wemos D1 mini.
I want to control 5 relays.
But I find on the net only cards with relays to command by low level.
I don’t know why, on one card with one relay it is command by high level and many relays on a card it’s always command by low level.
I wan’t to configure with push button.
Level 1 to 0 in my case.
And when I start my card wemos and when connection is ok all my relays works.
I must to send a command with push button by blynk for my relay let fall.
I don’t find this problem on differents forums.
I don’t want add component.
How I can do it (by code ?) for works correctly
Excuse for my language I’m French.
Thank you for your answers.

Trying to understand your question a little better. Are you asking how to control a high level relay with BLYNK button?
You can edit the value the button sends in the widget settings.

you can try that

#define RelayOn LOW
#define RelayOff HIGH

else you can edit button as @Toro_Blanco said.

Thanks for you answer
But your solution does not work.
Or I do not understand very well because on your photo, you take a virtual pin. I use a digital pin.
I have find an order to be put in the code of installation
Blynk. Sync All ();
it is better but when I begin there is always an impulse of my relays during some ms. And it is not good for my project.

Using digital/analog pins directly from the App will limit what you can do… Virtual pins give more flexibility and will allow such commands as the Blynk.syncAll()


As for the photo example given… whether using digital or virtual pin the 1 & 0 can be reversed to 0 & 1 if you want to send a LOW signal when pushing the button instead of a HIGH signal.

This is due to the fact that some ESP pins boot HIGH then go LOW, some boot LOW then go HIGH… this has nothing to do with Blynk…

1 Like