Simple add-on dusk-to-dawn switch for an LED candle?

I bought some great led candles, which run on 2 AA batteries (3 volt), and have a simple on-off switch. these came with a store demonstration switch at the end of two wires - press the button, it lights up even if the main switch is in the off position. You're supposed to remove this demonstrator, but what I want to do is add a photocell at the end of the wires to make a dusk-to-dawn switch. I tried just adding a simple photocell, but it works the opposite - in closes the connection when it detects light, not dark. I have looked and looked for a dark detecting photocell, but every prefab one is three-wire for 120v ac, and every construction circuit diagram (with transistor and resistor) has the LED in series between the sensor's emitter and the transistor's emitter. How can I construct a simple two-wire dark sensor inline on-off switch or circuit that will work in my appplication, without modifying the candle itself?

by biggreg1960
January 14, 2019

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