Brightness level about stc_diyclock

[zerog2k]

Ok apologies, I think I was looking at that ISR conditional wrongly.
I think this is the proper place to look for dimming:
https://github.com/zerog2k/stc_diyclock/blob/master/src/main.c#L491-L500
note that we are decimating the raw adc value from 8 to 5 bits
so from 256-0 (darkest to brightest) mapped to 32-0

I think this lightval acts sort of like a variable denominator in the fraction of duty cycle of led lighting. Larger denominator, shorter duty cycle; smaller denominator, longer duty cycle.

So perhaps try changing
lightval = getADCResult8(ADC_LIGHT) >> 3; to
lightval = getADCResult8(ADC_LIGHT) >> 2;
such that it's bottom range is 64 (darkest) instead of 32

[zerog2k]

You can try it and let me know how well it works.

[zerog2k]

The dimming is controlled somewhat creatively to get around some limitations (like running in ISR)- controlled here:
https://github.com/zerog2k/stc_diyclock/blob/master/src/main.c#L234

    if (displaycounter % lightval < 4 ) {

you can try playing around with different values (instead of 4), like 3?
from memory, lightval is raw ldr circuit adc values, and (I think?) it should be from 0-1023, and decrease (toward zero) when bright, and increase (toward 1023) when dark ?
this number here is trying to divide the raw adc lightval such that it skips lighting when displaycounter % (lightval < 4) == 0 if that's helpful

I don't have a way to test currently, but you can play around with this, and build/upload using platformio pretty easily

[in-sympathy]

thanks, but it doesn't work:

setting if (displaycounter % lightval < 3 ) {

would lead to weird display refresh misbehavior, especially with the 4th digit

any other ideas on how to make the brightness level in the dark as low as possible?

[in-sympathy]

thanks a lot, this seems to be doing the trick. would setting the value to 1 make it even darker then?

[in-sympathy]

Sounds like a plan- did just that and pretty happy with the results - the display is now a tad dim for some, but should not be a distraction at night anymore, so I guess mission accomplished - thank you so much for your help and for this awesome firmware 🙏🏻👍🏻

[p23f]

I solved the brightness problem by 3d printing a thin 0.6mm thick screen to fit in the bottom of the acrylic case to cover the leds.