Hardware modifications were made for the cold channel. The Vcc signal on the LEDs board was separated. Now it was time to test the whole solution using an external PWM signal generator. In our case, as before, it will temporarily be an Arduino Nano. The target control software will be uploaded to the Attiny25 MCU.

I connected the Led to the controller and prepared a sketch of the target application. The Arduino generates PWM signals according to the selected mode.

The circuit works as expected. I can independently control the brightness of the LEDs on both the cold and warm channels.

I still need to go back for a while to adjust the value of the output capacitor C19 for the cold channel. Perhaps C12 also needs adjustment. I'll have to check it out. After the final adjustments, the controller will be ready to develop the final version of the control software for the Attiny25 microcontroller.

The result of test both channels. The video show nine diffrent modes.