Darkroom Timer project

This project creates a usable darkroom timer that can:

• control turning on and off a safelight and enlarger
• has a settable timer for keeping the enlarger on, with manual override or cancel
• uses a backlit LED display (2 line, 16 characters), except when the timer is running and the enlarger is on, in which case the time is shown on a red 4 digit 7 segment display (TM1637)
• uses a rotary encoder to control functions, set timer
• has a buzzer/beeper for indicating end of timer

Resources for v2

better (hardware?) debounce for rotary encoders

https://arduino.stackexchange.com/questions/61861/will-a-simple-rc-filter-work-with-my-mechanical-rotary-encoder-or-do-i-need-a-s https://forum.arduino.cc/t/rotary-encoder-debouncing/361438/11 http://www.buxtronix.net/2011/10/rotary-encoders-done-properly.html