Ultra-flux RGB LED controller design and production - Power Circuit - Circuit Diagram

Introduction:

In this project, we utilized a Superfluid RGB LED with a common anode and a PIC18F25K20 microcontroller to create a variety of color combinations. The system features two operational modes: an automatic color sequence stored in the microcontroller's memory and a manual mode where users can select from one of seven possible colors.

Schematic:

Firmware:

PWM (Pulse Width Modulation) controls the RGB LED. Given that the PIC18F25K20 offers only two hardware PWM outputs, I implemented three software-based PWM outputs. I used TIMER0 and set up a manual mode PWM flat change interrupt.

Debounce:

To address the bouncing issue associated with button presses, which arises from the mechanical nature of switches, I employed a software debounce technique. While hardware solutions like RC delay circuits or Schmitt triggers could also work, they would increase costs. Thus, a software approach was chosen for this project. Here’s an example of how I implemented the debounce:

This method proved effective for my application.

Power Supply:

I used a 7812 voltage regulator to ensure a stable supply for the RGB LED and microcontroller. For the LM317 regulator, I calculated the output voltage using the following formula:

RGB LED:

Since the RGB LED has different forward voltages (VF) for each color, I adjusted the resistances accordingly. The calculations were based on the following equations: