that would definitely require them to not be "dumb" anymore. A simple sunset/sunrise detector can be had from a cheap photo-resistor. 30 minutes prior to suns

that would definitely require them to not be "dumb" anymore. A simple sunset/sunrise detector can be had from a cheap photo-resistor. 30 minutes prior to sunset sounds like it needs at least a micro controller with a real time clock and a lookup table with sunset times