Wemos D1 Mini Pin with 3.3v?

Hey guys,

have small problem and my actual knownledge about electronics isn't the best, just for small things.

I'm trying to achieve that a pin on the Wemos is on 3.3v all the time until I make a "digitalWrite(PIN, LOW)".

Can anybody help me out with this?

Pin D8 on Wemos is working like that. And I need a 2nd Pin that does the same.
In the Pin OUT I found out, that D8 got a pull down resistor. So should I solder anything anywhere wouldn't be a problem, but I don't know what :wink:

Perhaps you should explain what you try to achieve? Build in pull downs or pull ups are usually a good thing.

I use ESP8266-based boards for a lot of my projects, so might be able to help.

Your code :

should work, although make sure you've set the pin as an output first, then set it high initially by using something like :

pinMode(PIN, OUTPUT);
digitalWrite(PIN, HIGH);

If you use one of the pins with internal pull-up (D3, D4) then the high value will be 3.3V as required. If you use one of the other output pins, then you'll need an external pull-up resistor.

Note that some of the pins have other uses, and can also change the boot mode. There is also a limit on how much current the GPIO pins can handle. As @Christian-Me said, if you can explain what you're doing we can maybe provide more detailed information.

There's some good tips on choosing the input/output pins of both ESP8266 and ESP32 by The Hook Up on YouTube: https://youtu.be/c0tMGlJVmkw

For example some of the pins might briefly be HIGH (or LOW) during the boot up phase regardless of how you configure them in code. The same info can also be found from these pinout images he's modified to include such extra info.

The tips are for NodeMCU boards but the pin mappings are the same on D1 Mini's as far as I know.

2 Likes

The problem was an other. I already was able to set the pin's to right thing (on or off) but the buttons on the board I like to control have an other behaviour... so the problem by itself isn't existing anymore... now its just with the control board... have to dig in a bit more :slight_smile:

sry for late answer and thank your for your input!