Inspired by [GeckoDiode][1] (Instructables) and [smooth_jamie][2] (Instructables), I had to take up the challenge and build a version of my own.

Case design is original and is designed to work with a MAX7219 LED dot matrix module. Arduino sketch is based off [smooth_jamie][2] original work. I improved the RTC logic and fixed various LED hex byte arrays for minutes and animations that did not display correctly. In addition, the Alien Space Ship now completes the cast of characters.

[LED Matrix Editor][3] is a great tool to help create and troubleshoot matrix displays.

PARTS: Arduino Nano [Amazon][4] MAX7219 LED Matrix Display (Red and Green LEDS) [Amazon - Green][5] [Amazon - Red][6] DS1307 Tiny RTC Module * REQUIRES PCB MODIFICATION * [Amazon][7] CR2032 Lithium Battery 8 ohm speaker [Amazon][8] 1K ohm Resistor SPST Momentary Push Button [Amazon][9] SB400 Solderable PC BreadBoard [Amazon][10] Micro USB Interface Power Adapter Board 5V Breakout Module [Amazon][11] 5 VDC Source - I used a USB power supply for a cell phone #4-20 X 5/8" Plastic Screws, QTY 4 [Amazon][12]

Arduino Sketch - Included in Thing Files
SpaceInvadersClockRepRapTodd03152020.pdf

Note: Tiny RTC module needs R4, R5, R6 and D1 removed from PCB. R6 requires a wire to complete the circuit after removing the resistor. Now that the faulty recharging circuit is disabled, use a standard lithium 2032 battery to keep time when power is removed.

Arduino libraries required: [MaxMatrix] [13] - interfaces with the series of 8X8 LED displays [JeeLabs RTClib] [14] - Real Time Clock - DS1307 Tiny RTC Module

[1]: https://www.instructables.com/id/Space-Invaders-Desktop-Clock/ "GeckoDiode" [2]: https://www.instructables.com/id/Space-Invaders-Clock-on-a-Budget/ "smooth_jamie" [3]: https://xantorohara.github.io/led-matrix-editor/ "LED Matrix Editor" [4]: https://www.amazon.com/dp/B0713XK923/ref=cm_sw_em_r_mt_dp_U_kRDpDbA0P0QSQ [5]: https://www.amazon.com/dp/B07FNHKD5W/ref=cm_sw_em_r_mt_dp_U_URDpDb9D12WSD [6]: https://www.amazon.com/dp/B01EJ1AFW8/ref=cm_sw_em_r_mt_dp_U_WSDpDbPNDEVHA [7]: https://www.amazon.com/dp/B079P7DWTB/ref=cm_sw_em_r_mt_dp_U_GUDpDbJ118R6C [8]: https://www.amazon.com/dp/B0177ABRQ6/ref=cm_sw_em_r_mt_dp_U_wVDpDb7DPBM2Z [9]: https://www.amazon.com/dp/B07QJ9JS4Y/ref=cm_sw_em_r_mt_dp_U_xWDpDb1F77EHA [10]: https://www.amazon.com/dp/B01MR9GF87/ref=cm_sw_em_r_mt_dp_U_.WDpDb4ARFFFZ [11]: https://www.amazon.com/dp/B07B5ZDLJY/ref=cm_sw_em_r_mt_dp_U_EMDpDbYQT9736 [12]: https://www.amazon.com/dp/B00GDYV7EA/ref=cm_sw_em_r_mt_dp_U_z-DpDbMJ7CF43 [13]: https://github.com/riyas-org/max7219 [14]: https://git.jeelabs.org/jcw/rtclib

UPDATE: 03152020 - Fixed sketch to display midnight correctly. Updated line #1205 - case 12: case 24: to case 12: case 0:, now correctly evaluates time at midnight. Thing file updated with code fix.