Okay, let's begin.

Time to select our components!

For the main board, I'm currently using Arduino Uno because that's what I have but if required I may move to Arduino Mega 2560 (either compatible board or 3D printer controller board which basically is Arduino Mega with extra hardware thingamajigs)

For the display, I have few selections:

• I2C OLED display (long one, not 128x64)
• RepRapDiscount Smart Controller (basically a display, rotary encoder with click button, speaker, a button and a SD card reader with only 20 wires)
• 8x8 LED matrix display using MAX7219
• I2C 16x2 character display (YWRobot addon board, uses Philips FCF8574 chip)
• RepRapDiscount Full Graphic Smart Controller (128x64 monochrome graphic LCD with all the features of Smart Controller)

For the speakers I plan to use 0.5~1W paper cone speaker with the venerable 2W tiny amp with adjustable volume.

For the nighttime dimming function I'll just use a transistor circuit. I don't think it needs any fancy microcontroller features but if I have any pins left and if I don't muck the code up too much I might add the fancy PWM dimming.