Get ALL the components you need. It might sound simple, but I went through lots of trouble to get it.

Install Eagle CAD (free version)

Clone repository https://github.com/atheros/backtothefuture-clock

You'll find sourcecode, schematics and board designs there.

Create (etch and solder) 5 PCB from big-module-shift and big-module-test - those are the display PCBs and drivers for 14-segment displays.

Create 2 boards of each of the following:

• date-led
• date-shift
• time-led
• time-shift

Create (etch and solder) one PCB of each of the following:

• temperature-led
• temperature-display
• display-controller
• main, a.k.a Time Circuit Clock PCB

Solder display PCBs to display driver PCBs using angular pin headers and in case of 14-segments, an additional ribbon cable connection is required.

Connect driver boards with ribbon cables. 7-segment display boards and led board uses 10 wire cable, 14-segment displays use 12 wire cables.

Note that there is no 12 wire IDC plug, so I used 14 wire plug and left the last two wires unconnected on the board.

You can see the connection here:

Red wires are for 14-segment displays, blue for 7-segment displays.

Load the sketches:

• DisplayController to display-controller board
• MainController to main board

Make sure you remove the LED from pin 13 from the Arduino on the Time Circuit Main board or your keypad won't work correctly.