Logarithmic Dimming Curve

[testo94]

Hey Li,

I just stumbled across your project (it was somewhere in my Reddit feed) and I'm just blown away by it.

Right now I hadn't had the time to read all of the source code but it looks way too good to not give it a try.

Some years ago I did a way more simple approach to make my not so smart built in LED a little bit smarter and what I really would love to see in your project is a logarithmic dimming curve. I have 2 tanks beneath each other (one with a Week Aqua LED and linear dimming and my selfmade) and the logarithmic is so much more satisfying for the eyes.

So I would like to drop my snippets auf the Arduino Code here to hopefully see it implemented:

// The number of steps between the output being on and off
const float pwmIntervals = 22500;

//Replace 4095 by the amount of PWM steps
 // Calculate the r variable (only needs to be done once at setup)
 R = (pwmIntervals * log10(2))/(log10(4095)); 
 
 brightness = (4095 * pow(2, currentStep / R)) / 4095;

Greetings Testo

[oldrev]

Hello,

Right now, I'm using the CIE1931 lookup table for dimming, but my PWM resolution is only 8 bits. That's because I've set my PWM frequency to 24kHz to avoid inductor whining.

You can check out the code here: https://github.com/oldrev/borneo/blob/a10c1138033f7684348dc249999724c709656411/fw/lyfi/main/src/led.c#L84

[oldrev]

Great news!

The dimming frequency has now been upgraded to 24kHz, and the duty cycle resolution has been upgraded to 10-bit. The code implements linear, logarithmic, and CIE1931 algorithms simultaneously.