Changing a function for wide range contrast

[Deoptim]

Hello. There is a hack in which you can reduce the contrast of the display to the smallest values:

// 1. Fundamental Command Table

void SSD1306Device::setContrast(byte contrast) {
    byte val;
    if (contrast < 193) {
        //0x00 value of pre-charge period and vcomh allow us to wide change contrast of display
        setPrechargePeriod(0,0);
        setVcomhDeselectLevel(0);
        val=round(contrast+45*1.074);
    }
    else {
        //reset pre-charge period and vcomh to default value
        setPrechargePeriod(2,2);
        setVcomhDeselectLevel(2);
        val=contrast;
    }
    ssd1306_send_command2(0x81,val);
}

Video Preview: https://drive.google.com/file/d/1vcizbV8zYmK-5RECyfEOGb9WmdbUL0Ce/view?usp=sharing

[datacute]

Hi Deoptim. I think you intended some additional parenthesis: (contrast + 45) * 1.074 ? I've found that different screens can have very different responses to the contrast settings. Using the internal current reference (command AD documented in SSD1306B_v1.1 datasheet) helps to get different devices behaving in a more consistent manner, and the two IREF options result in a big difference in brightness too. My desire with this library is to keep it as small as possible, so I won't be changing setContrast as that is intended to map straight to the setting of the contrast control register, but I'll think about adding some additional examples. Also - I suspect user applications are probably better served with a small number of contrast/brightness options, including some really dim settings for adjusting how the display appears in the dark, and some really bright to use outside, and a small number in-between. These are possibly better implemented as small lookup tables for the various settings that affect the brightness.

[Deoptim]

Hello. Yes, you may be right. But I made these settings based on the video from YouTube example: https://www.youtube.com/watch?v=hFpXfSnDNSY

And as you can see, those settings fit for my display as well. (I shared the video link above) Good luck.

[SpenceKonde]

I suspect user applications are probably better served with a small number of contrast/brightness options, including some really dim settings for adjusting how the display appears in the dark, and some really bright to use outside, and a small number in-between. These are possibly better implemented as small lookup tables for the various settings that affect the brightness.

I agree 100%. It looks like this may already be implemented, at least in some form?