What is your project about? Why did you decide to make it? How does it work? Show us with images and videos!


  • The dimensions of the board are less than 100x100mm.
  • All components are output, soldered even by a beginner
  • The number of components is minimized!
  • The system consists of two boards: the bottom (all control electronics) and the top (lamps and backlight LEDs)

Hardware Chips:

  • The heart of the board is the full-size Arduino NANO, which means easy assembly and firmware
  • Power supply for the entire circuit - 5 Volts
  • The high voltage generator is swinging the PWM channel of Arduino
  • The voltage of the generator is adjusted by a resistor with a twist
  • Time sets RTC DS3231
  • 3 buttons for setting the time and alarm
  • Alarm squeaker
  • Illumination of indicator lamps

Software Chips:

  • “Busting” the figures once every half an hour, preventing the indicators from oxidizing
  • Smooth change of brightness of a point and illumination of lamps
  • Setting the brightness of numbers, “dots” and backlight
  • Two brightness modes depending on the time of day
  • 4 indicator switching modes
  • 3 lamp backlight modes

Button control:

Time setting:

  • The left button is a choice, the rest are “more” and “less”
  • Hold “selection” - time setting
  • Click on “choice” - change the setting hours / minutes
  • Click “more” and “less” - time change
  • Hold “select” - return to watch mode

Setting effects. In watch mode:

The central button toggles the lamp backlight

  • breath
  • constant light
  • off

The right button switches the modes of turning numbers

  •  No effect
  •  Smooth fading
  •  Number Rewind
  •  Cathode Rewind
  •  Train
  •  Rubber

Holding the center button enables / disables “glitches”


Arduino NANO Rev3.0

RTC DS3231

DS3231 micro


Card Slots

Pin rail

Electrolytic Capacitor 4.7 uF 350V

Trimmer resistor 470 kOhm (500 kOhm possible)

Inductance 220 μH

Diode HER106

Transistor IRF840PBF

Optocoupler TLP627 (F) DIP-4

K155ID1 decoder

5mm LEDs

3mm LEDs

0.25W LED


        150 ohm

        470 ohm

        10 kOhm

        100 Ohm - 3pcs

5 V power supply (charger from smartphone) - 500 mA minimum