Text Too Bright - Backlight POTS to control the Textlight?

unangst · Post by **unangst** » May 16th, 2006, 2:48 am

Wiring up went well on my first LCD screen. (HD44780; 4x40)
Thanks to all that have developed LCD Smartie!

Anyways, here's the problem:

The text on the screen is too bright. This brightness makes the screen a bit hard to read. The best way to describe it would be the opposite of 'shadowing'... if line 2 and 4 are blank and the text on line 3 seems to bleed into lines 2 and 4.

I looked at the brightness control here:
http://www.lansley.co.uk/forum/phpBB2/v ... brightness
and decided to use a 10k-ohm micro-size potentiometer (50vdc / 0.1W) from RadioShop. But this only seemed to dim the backlight and not the text.

Anyone have any ideas? Thanks!

_X7JAY7X_ · Post by **_X7JAY7X_** » May 16th, 2006, 3:06 am

The top pot in that diagram is for Contrast. The bottom transistor is for the backlight. Did you replace the transistor with a pot?

Did you try turning the contrast pot?

J