Imagine driving at night and seeing a radio tower in the distance. At the top, a red light appears to brighten and dim instead of just blinking on and off. How can this effect be accomplished with a 555 timer? I assume the charging and discharging times must be increased, but I don't want to change the on/off frequency of around 1hz.
So, quickly hacking together something derived from the sort of things suggested by John and Doug, would this do what you want?
Needs a large electrolytic value to get the timing, though, and not really a 'good' circuit [far too finicky], but it's interesting to play with. By the way, it's a standard red led: the intensity, relative to the rest of the scene, overdrives the camera sensor and just makes it look white.
