How to adjust brightness/contrast of LCD 16x2 or 20x4 I2C

Projects Programming
1

hi all,

i've a problem to read the lcd dependent of room-light

as the module ist mounted in a way i can't reach the trimmer to adjust.

i there a way to adjust by code /sketch over the I2C-interface ?

thanks in progress

2

Your topic was MOVED to its current forum category which is more appropriate than the original as it has nothing to do with Installation and Troubleshooting of the IDE

3

and whats the solution, UKHeliBob ?
where to find my question now ?

4

Maybe. Have you looked at the data sheet or operating manual for your unindentified display?

5

i am searching since half an hour but didnt find anything usefull for this issue..

6

the displays here are 16x2 and 20x4 chars per I2C for nano and mega2560,
this works fine, but it would by nice to adjust contrast/brightness for best reading..

7

Plenty of tutorials show up in a search for "16x2 lcd contrast adjustment".

If you have one of those displays, there is no software command option. Move the trimmer elsewhere.

8

i had found some videos but basing on my hearing problem i cant use this !

does nobody can give a link to a suitable tutorial or advice ?

9

anyways : in ```
#include <LiquidCrystal.h>

there is no function what covers..

is there any other library ?
10

no.
You must adjust the trimmer to make it visible.
You can't solve it with code.
Adjust the trimmer.

11

thanks, noiaska !

text is visible but i.e. sunlight oberblows it like screens in sunny situation..
then i'll mount it on a x-axis-turnable manner to reduce
light effects..

12

buona sera,

i've found in github some code with

<#include \<LiquidCrystal.h\>...  // Switch on the backlight
  pinMode ( BACKLIGHT_PIN, OUTPUT );
  digitalWrite ( BACKLIGHT_PIN, HIGH );
>

seems there are people dealing with apperance of lcd-screen..
13

Are you using the library that the code snippet came from ?

14

hi,

i've not tested it until now..only looking in the examples to the libraries..

i.e. something with Backlight(HIGH); appears in more than one library..

16

good morning,

the project is a track diagramm control panel, on which the two lcd-pnaels will reside

the lcd is a default type " hd44780 2004 lcd display"
a picture is available from many sources..getting image from them would be illegal :shushing_face:

if i try to foto this with smartphone the light-circumstances will be influenced by my bodies shadow..that would not show the whole truth :face_exhaling:

at least mechanical making the mounting-angle of the whole panel
adjustable in a certain value-range will take the best effect :slightly_smiling_face:

at least thanks for your interest..have a good time

17

Exactly which LCD library are you using ?
Not just its name (there are several with the same name) but exactly where you got it from

18

hi,
mostly i got it from AZ-Delivery here in Germany..

19

hd44780 displays are an old design with limited contrast. They are not suitable for all situations, such as where there can be extreme differences in ambient light levels.

De-soldering the contrast pot from the i²c backpack and replacing it with a pot mounted on the front panel may help a little.

Connecting an LDR to an Arduino analog input pin and connecting an Arduino PWM pin to control the LCD backlight via a transistor could also help.

Some hd44780 are available with "transflective" LCD panels, which are much more visible in very bright conditions because they use ambient light for illumination. Some of these transflective displays also have a backlight, which means they are still visible in low ambient light.

OLED displays have a much higher contrast and are readily visible in a wide range of ambient light levels. They are however more expensive for an equivalent size, and will require different Arduino libraries and changes to your sketch.

20

thanks PaulB,

ok, as i'm a little handicaped i'm carefully with soldering genereally :thinking:

so - as i have different priority to dealing with visual things -
the mechanical way seems to be the quickiest solution at now

if adjusting the angle does not fully satisfy one could add aperture (or fascia or..?)
round the displays to limit light-introduction as is usual with teleobjectivs..

21

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