555 timer using PWM to throb an LED?

I'm trying extremely hard to figure out how to make an led throb with a 555 timer using PWM. What I have figured out how to do so far is how to make a 555 circuit with a potentiometer and manually throb it with the pot. But I don't want to just keep turning the pot to throb the led. Is there a I can put a potentiometer in the circuit to control the speed of the throb rather than dim the led?

I need to use PWM for the throbbing. And the throbbing speed needs to be adjustable with a potentiometer.

I'm really new to circuits, but I'm learning a lot. Can someone point me in the right direction? This is an extremely important project for me.

frollard6 years ago
You need to replace the pot with a transistor, and feed that transistor a sinewave of voltage from another 555 timer smoothed out with a capacitor. Exactly what values to use can be a bit finnicky.
SpiffyChee (author)  frollard6 years ago
wow. thank you so much. This makes a lot of sense. Do you know of any place on the internet where i can find an example of this type of implementation of a 555 and capacitor to get the right sinewave of voltage?