Considerations to make this contraption work ?

[Externet]

Hi.
Made a block diagram sketch as shown below.
Intention is to have the LED fully energized only during the rising of the 1Hz sharkfin waveform until it reaches 2.5V level, and off when the waveform at 'C' decreases by the comparator discharging it.
And the coil proportionally energized with the rising/decreasing of the 1Hz sharkfin waveform at 'C'
Circuit to work only at dark.
Comparator perhaps LT1720 operable on single supply to less than 3V, transistors perhaps Darlingtons, or your suggestions.
Rc is the charging, Rd the discharging of 'C'
Sorry, am not good with simulators either.

 

[Alec_t]

With that set-up the LED will be on while C charges up to 2.5V, then goes off. C continues to charge, since Rd provides positive feedback. There ain't no sharkfin .
Personally, I'd probably use a CD4093B as a 1Hz oscillator, gated by the dark sensor.

 

[Externet]

Thank you.
I see that goof now. Better use another transistor to discharge C trough Rd.
The 'on when dark' works dusk-to-dawn, keeping the circuit on all night.