/diy/ - Do It Yourself

Working on the lighthouse circuit from earlier thread. The idea was to light up some leds sequentially with a 4017, but linearly ramping the off->on & on->off transitions of the leds with a PWM signal.

So far I've managed to breadboard an oscillator circuit with a 555 + npn/pnp + op-amps that generates a very low-frequency triangle wave signal with an amplitude of ~0.1 to 3.5 V.
Now I'd need to make a PWM circuit with 555/556 to convert the triangle wave signal into a square wave with 0..100 % duty cycle.

Pic is a rough sketch of the circuit that I'm working so far.