If one wants to display 3 digits, three displays should be used. There are many circuits available for 2-digit up/down counter but using a microcontroller reduces components and space on the board but ...

This is a simple 0 to 9 counter circuit constructed using Arduino! Here, a common cathode 7-segment LED display is connected to Arduino for displaying the digits. The code (Arduino sketch) allows push ...

Speaking of hardware, the clock is a pretty standard mashup of an Arduino Pro Mini clone and a DS3231 I2C clock. The Neopixel strips are 60-per-meter WS2812B LEDs with two LEDs per digit segment.

A very small parts count makes the Nanino much less expensive to produce in quantity than even the official Arduino single sided board. For an introduction to etching your own PCBs at home, we ...