This post is about building a simple LED controller circuit. Several articles were published on this subject during last 2 years. Here is just one link to similar design that can be useful. Search the site for more information. Current design relies on well-known technique to control output voltage by changing its duty cycle. Pulse Width Modulation is a common way to control output voltage. Basically it’s a modified version of the code used in fading LED post. Instead of continually circling through PWM values a switch is used to increase LED brightness in preset steps. I suppose that you have a basic knowledge of PIC assembly instructions and can successfully build and program your target device. In any case the source code and a precompiled HEX file are available at this link with additional comments. I always build and test all published prototypes so if you use the same components and copy the code exactly the circuit should work without any problem. Fill free to ask me additional questions through contact section at the top menu. In the next pages I’ll explain in more details how this prototype was build and tested.