How to change the display contrast?

[mrblp]

Hello all,

I got a second NXT brick yesterday. The display of this brick has really bad contrast setting compared to my first brick. The active square gets really dark when the brick is switched on. So the classic contrast setting seems to be to much.

But how to set or change the contrast settings on the brick? I did not find anything to change the contrast setting

Thank you!

Bye marvin

[mattallen37]

Try running this NXC code. (I think) 90 is the default, so first try that to see if it changes it (in case it wasn't default when you got it), and then you could try other values (the lower, the dimmer).

Code: Select all

task main()
{
  SetDisplayContrast(90);;
  Wait(100);
  PlayTone(1000,100);
  Wait(1000);
}

Note, for some weird reason, it requires TWO semicolons after the "SetDisplayContrast" command, in order to compile using 3.3.8.9. Also, since that issue, I have not tested the command in practice.

[mrblp]

Hello,

Note, for some weird reason, it requires TWO semicolons after the "SetDisplayContrast" command, in order to compile using 3.3.8.9. Also, since that issue, I have not tested the command in practice.

I had no problems using just one ";".

I am sorry but this is no solution. Yes, the display contrast can be changed the way you described it with the enhanced firmware installed. But the contrast setting is being reset when the program stops. To weired.

I think I have to patch the firmware and have to add a function on the "Settings"-Page. This setting may be saved in the NVConfig.sys file. Funny LEGO made the contrast setting fix - most electronic devices with dot matrix display allow setting the contrast by the user.

Bye marvin

[mrblp]

Hello,

I found out the contrast setting is made static in the firmware. This setting may be changed using a hex editor, searching for the right value and replacing it by a better value.

Because this is a bit tricky and may even destroy your hardware when using the wrong way I won't publish the codes here. It seems to me that there are not a lot people with a display with lower contrast.

Bye - marvin