Introduction: Back to the Future Clock - RTC MODULE

Build your own clock !

Find all needed components just right there :

I designed this little clock because I'm a big fan of the movies and I couldn't really find an equivalent on the internet. Either I found models that were too simple that did not look too much like, or models that were too complicated to make, which is quite demotivating.

If you have some basic notions like :

  • Soldering
  • Stripping a wire
  • Read a wiring diagram

It should go well !

The interface is not exactly the same as the movies but everybody recognize anyway !

The first line (red displays) and last line (yellow displays) are fixed in the code, you can put whatever you want (date, hour...).

The green line is a clock animated by a RTC module.

Step 1: Components & Tools

Bundle available here :

Available on my website (above):

  • 9 displays (3 reds, 3 greens and 3 yellows)
  • 6 LEDs (2 reds, 2 greens and 2 yellows)
  • 1 Arduino Nano
  • USB to mini USB cable
  • 1 RTC module
  • 1 Power supply (5V 2A)
  • 1 Connector
  • 4 Resistors (270 Ohms)
  • heat-shrinkable sleeve
  • Wire cutter
  • Electronic wires multicolor
  • 0.75mm² wires (black and red)
  • Wago terminals

Not available on my website (yet):

  • Wire stripper
  • Soldering iron
  • tin
  • super glue
  • CR2032 Battery
  • Double sided tape

Step 2: 3D Printing

You can print the part like this : PLA, infill 20%, layer 0.2mm

Step 3: Assembly

I used Super glue to assemble every 3D printed part.

Step 4: Painting

You can use a "metal grey spray paint" that you can find in every DIY shop.

Step 5: Solder the Resistors on LEDs

In this step you have to solder 270 ohms resistors on 4 leds which are powered (see diagram).

  • 2 leds (one red, one yellow) will be permanently powered
  • 2 green leds will be piloted by D12 and D13 Arduino outputs
  • 2 leds (the other red and the other yellow) will be always off.

Step 6: Glue LEDs

Glue every LEDs in the dedicated holes.

In this step you can choose which (red and yellow) LEDs will be powered or not.

Step 7: Displays Wiring

You can see on the diagram that you have to chained every display by color (red,green and yellow).

One "clk" input by color (A0,A1 and A2).

You have to solder one wire in each DIO display input (D3 to D11).

Step 8: Displays Fixing

To fixe displays in the dedicated holes, you can put a little piece of double-sided tape in the two sides of each display.

Don't forget : the red displays on the top, green displays on the middle and yellow displays on the bottom.

Step 9: Displays and LEDs Powering

To gather every "+5v" and "Gnd" of each component, you can use "Wago terminals" but it also works with classic dominos. The wires between the connector and the terminals are 0.75mm² of cross-section.

Step 10: Inputs Wiring

To wire every inputs (Displays, LEDs, RTC clock) you can also take a look to the global wiring diagram (STEP 13)

Step 11: Upload Arduino Code

Connect your arduino with a USB => mini USB cable and upload the code.

Check :

  • Arduino Nano
  • ATmega328P (Old Bootloader)

You have to add these two libraries :

  • arduino-tm1637-master
  • RTClib-master

Available on my thingiverse project too (I cannot up a zip file here) :

Step 12: Add Labels

I used a self-adhesive sheet because I think it's the easiest way to stick the labels.

Step 13: Global Wiring Diagram

Step 14: Et Voilà !