Let's Control It

Hi, I'm on build 20181220 on a Nodemcu V3. I try to connect an LCD 2004.
On the I2C scan it finds the lcd on address 0x27.
Now, when I enable the device and write "IP %ip%" on the first line, the display remains blank.
Also, I'm not really sure what interval is for.
Thanks for any hints.

Do you connect "VO" pin (contrast)

potmeter adjustment ?

yes

Hey thanks for the reply. I connected the four pins GND,VCC,SDA and SCL.
EDIT: The tip with the potmeter helped but the highest contrast is still barely visible.

The text is weak in dark color instead of being bright and white on the blue background.

Display needs 5V.
Use a level-shifter for SDA and SCL.

Okay, I will try that, thanks.

Good.

Seen this one?
https://www.letscontrolit.com/wiki/inde ... LCDDisplay

As I am a beginner that line didn't ring a bell for me when I read it.
Luckily I have bought plenty of different parts in advance and I found a level shifter.
Now it works like a charm.
Maybe the wiki entry could be dumbed down for beginners like me, that think it's enough to plug&play.
Anyways, thanks a lot for the advice. I'm looking forward to play with that lcd

(for beginners like me: lv is 3.3v, gnd is gnd, lv1 is sda old, lv2 is scl old
then on the other side: hv is 5v source, gnd is correlated gnd, hv1 is sda new, hv2 is scl new)

I like to sugest to author of plug-in for I2C LCD 2004 to extend range of I2C address to 0x4f (http://www.ti.com/lit/ds/symlink/pcf8574.pdf page 13 ).
Thank you

velja wrote: ↑12 Dec 2019, 09:57 I like to sugest to author of plug-in for I2C LCD 2004 to extend range of I2C address to 0x4f (http://www.ti.com/lit/ds/symlink/pcf8574.pdf page 13 ).
Thank you

I added an issue for it, so it will not be forgotten.
See https://github.com/letscontrolit/ESPEasy/issues/2813

Nice,
Thanks!

Hello,

I have connected an ODROID 20x4 LCD from Pollin:
https://www.pollin.de/p/odroid-h2-i2c-2 ... dul-810957

I can see the text on the display, but it is also weak and dark and not white as it should be. If I reconnect the display while ESPeasy is running, I get (of course) random characters, but they are bright white!
So it doesn't seem to be a matter of voltage. The display is specified for 3.3V by Pollin and in the ODROID guide it is also connected to 3.3V.
https://wiki.odroid.com/odroid-h2/appli ... d#tab__h21

So it seems to be a matter of initialization...?

Thanks for your help!

I found that the display should have a charge pump to get the needed LCD voltage if VCC is 3.3V.

But this charge pump is not fitted on my display, so it is not for 3.3V use Thanks, Pollin ...

But fitting this charge pump may be an alternative to 5V and I2C level shifters.
https://www.element14.com/community/gro ... cds-to-33v