My project adapted the potentiometer as my switch.  The LEDs are placed in the picture frame.  I used oil pastels to create a sky to make the lights imitate stars.  Initially, the sun, which is connected to the switch, is above the frame.  When the sun is above the frame, the lights are very dim.  pushing the sun behind the frame, the moon, which is also connected to the switch, moves above the frame.  This movement turns the potentiometer so that the LEDs brighten, mocking the transition from day to night.

I soldered the LEDs together with blue wire. I then hotglued them into the back of the ‘sky.’

They are in a parallel circuit so I could use four LEDs( all blue and white) with a 9 volt rechargeable battery.