Tag Archives: pwm design

Final tweaking to Artemis, the smart paludarium controller

Getting ready to have the main PCB built in China, I discovered some things that made me rethink… And make some pretty radical changes to the PCB… Enter v1.01!

Change 1: PWM for LEDs in high-res

The most major change “came to light” when I played with a prototype to control my new LED panel. Right now it uses PWM directly from the Arduino, so that is 256 steps (8 bit resolution).

But especially at lower light intensities I can see the LEDs take their steps. As I also have 16 channels controlled by a PCA9685 chip which is 12 bit resolution (so 4096 steps), I decided to use the PCA9685 outputs to run lighting. This in turn meant I needed to rethink which outputs work on 12V and which ones work on 24V. In the end I solved the puzzle and came up with a clean design:

Artemis v1.01: Changes to the layout of 12V and 24V power feeds and connectors. Note the large 6 pin connectors on the left: They are 24V RGB-CCT outputs now run from the PCA9685 PWM chip.
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