Countdown with 2 displays and some

It's a "simple" project but with some challenges and functions. The only thing that is needed is the programming, so no hardware! The hardware is as following: - Arduino Nano 3 board - 2/4 buttons - 1 input signal - 2 relay boards - 2 displays TM1637 Option: LED-strip WS8212/WS2812 The following functions are needed: As the title describes its a time countdown on 2 displays (same time on both displays) with 2 options of time by a press of 1 or 2 buttons : 2.40 minutes (160 seconds) and 3 minutes (180 seconds). The displays are showing ”02:40” or “03:00” before start. When the “start” button is pressed or via the input signal, the countdown is started. When the count down is at 10 seconds left, 1 relay is pulsing every second until the countdown is reached and when 0 the relay is on until the same input is triggered or the “stop” button is pressed. The other relay is triggered af 5 seconds after the countdown reached 0 seconds if the input of “stop” button is not pressed. After one of those is triggered the countdown is re-set to the set time (180 or 210 seconds). The following needs to be adjustable: - Both the start times (180/210 seconds) - The relay pulse start time (at how many seconds the relay starts to pulse) - The amount of pulses per second for the relay - When the second relay is trigged (after how many seconds the relay is on when the countdown is 0) Option: When starting up the Arduino the amount of LED is counted , so the length doesn’t matter when the countdown is active or defined in the config. When powering up the LED strip has a starting color. Every time a second is passed “X” amount of LED is switched to the second color and when the last 10 seconds the LED strip needs to flash until the counter is 0. And after the “stop” button is pressed or the input is trigged the led is set to the starting color. The following needs to by set in the config: - Starting color - Second color - The amount of seconds that the strip flashes until 0 And the wiring diagram.