Nick Leijenhorst writes:
I wanted to dim my room LED lighting with a potentiometer, and decided on creating a solution from scratch to make it more fun and educative. I decided to go with the fairly well-known 555 PWM circuit. To decrease size and for learning purposes I decided on using surface-mount components for the first time. The reason I wanted to make this 555 PWM circuit is actually just to see if I could solder SMD components on home-etched PCB’s, and to see how hard it actually is.
Neat little circuit.
However if you want to cut down on components even further, try a micro ;-) I find it even
works out cheaper as well.
I’ve used a little PIC12F615 before to do PWM using the hardware generator – it just runs a loop, reads a value from an input potentiometer, then sets the PWM duty cycle. You can then do cute things like having a nonlinear response to knob position – I once wanted to control the _power_ delivered to something rather than the _voltage_, so I rigged up the PIC to produce a parabolic response.