Arduino Word Clock - Customisable and Easy to Build




About: Hello, I've recently started making and sharing home DIY projects. I'm really enjoying making these and speaking with the people who make one of their own. It has become my new hobby and I hope to be able to...

My partner saw a clock in a shop that told you the time by lighting up words to write a full written sentence from what seemed a jumble of random letters. We liked the clock, but not the price - so we decided to make one of our own design

The face of the clock can also be easily swapped once complete to change its style or look as often as you like

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Step 1: The Video...

If you prefer to watch a video here it is, otherwise read on!

Step 2: Print the Main Body

The first thing you need to do is print the main body of the clock. This print is the largest of all the prints and may take some time depending on your chosen layer height. You can find the 3D files to download for free here:

The main body is called CLOCK-BODY.stl

Step 3: Preparing Adafruit Neomatrix

Whilst that is printing you can start assembling some of the electronics. You'll need three wires about 9cm long to start with. Strip a bit of insulation off each end so that we can solder these between our Neomatrix and Arduino Nano.

We will solder these three to the Neomatrix. If you look on the reverse of the Neomatrix you will find two groups of three soldering points. One has a point labelled DOUT and the other has one labelled as DIN. We want to solder each on of our three wires to the group of points with the labels, GRND, 5V and DIN (Digital in).

Once you have all three attached we will add a 330 Ohm resistor to the wire we attached to digital in. This the colour markings of a 330 ohm resistor (Orange-Orange-Brown-Gold):

Step 4: Attach Neomatrix to Ardunio Nano

The three wires (one with a resistor on it now) can be attached to our Arduino Nano. Please take a look at the circuit diagram provided. You'll see you need to solder them as follows:

NeoMatrix | Nano

GRND ---> Ground

5V ---------> 5V

DIN ----Resistor----> D6

Step 5: Solder Wires to RTC DS3231

Next up we will connect the RTC or Real Time Clock. This is the board which allows our Arduino to remember the time even when it is disconnected from the power. The RTC we are going to use a DS3231.

You'll need to prepare four wires this time, and they'll need to be about 6cm in length each. Again strip the ends as we will be soldering these to our components.

Solder one of each of the wires to the connections labelled SDA, SCL, VCC and GND

Step 6: Connect RTC and Nano

This will now be attached to the Arduino Nano. Again you can either follow the wiring diagram or for quick reference here is a small table.

RTC | Arduino VCC ------> 5V (This wire will need to be soldered along with the existing wire from the Neomatrix)

GND ------> Ground

SDA --------> A4

SCL ----------> A5

Step 7: Upload Code and Test

It's at this point that you can upload the code to see if everything is working as expected. You can find the code attached or you can find a continually improving version here on Github:

Step 8: Attach Neomatrix to Main Body

You'll notice the Neomatrix has some mounting holes running through the centre of it. This should align with the six pins on the printed part. We need to ensure that you mount it correctly - the corner of the Neomatrix with our wires attached needs to be located on the corner of the print with the smallest inlet for the light which is the one i'm pointing to in the second image above.

Use some dabs of hot melt glue on the pins that protrude to secure it into position.

Step 9: Print the Stand

Now print the part for the clock stand. You can print this in a different colour if you like. I've done mine in white for some contrast.

Step 10: Position and Attach Electronics

We need to glue our other electronic components (the nano and RTC) into place in the back of this enclosure before fixing it to the back of the clock. Start with the Arduino. You need to make sure that once the Arduino Nano is secured you can still connect a USB cable to the it's USB port to power it. There is a hole for this.

The RTC DS3231 can then also be glued adjacent to this in the same manner.

Step 11: Attach the Stand and Main Body

Next up is attaching the stand. You can use the letters that you can already see on the clock front to ensure you glue on the right way up! Position it in place on the back and get the glue gun out again and seal it into place.

Notice how you can still access the USB port through the hole on the back - if you can't on your you'll want to fix this before securing the stand in place.

Step 12: Fitting Light Diffuser

To cut the tracing paper to size, lay the Clock on a single sheet (lining it up with one of the corners) and trace around the other two sides. Next cut out this shape, but cut just inside of the line ans we don't want the tracing paper to be bigger then the clock face or it will interfere with changing the clock faces later.

Apply some small dabs of glue to the corners of the clock body and then position the tracing paper onto these. Whilst the glue is setting stretch the sheet our between the corner to try and minimise any wrinkle in the sheet.

Step 13: Quick Test So Far

At this point I connected a USB battery pack to the clock to check that everything is still working as it should, luckily mine was just fine.

Step 14: Print a Clock Face and Drop Into Position

Now we just need to print and slide our clock face over the front of clocks main body. It's as easy as that. :)

Step 15: Print Your Own Face

If you want to customise your clock you can design and print your own stylised clock face. You could use multiple colours of plastic, assemble it from wood or cover it in glitter mixed with glow in the dark paint. Whatever takes your fancy!

If you want to make your own face, attached is a drawing showing the measurements you'll need to help it fit onto the front of the clock.



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10 Discussions


10 months ago

Worth trying ... thanks for sharing!


1 year ago

This is a nice build. I like these clocks.

I note that you never illuminate the "O'CLOCK" nor the "MINUTES". MINUTES would be easy but you'd have to change the 'R' character to an apostrophe in your mask if you wanted to show O'CLOCK.

Also if you moved 'HALF' over to the right one space you could use the unused 0,2 position to show 'A' so you could say "IT IS A QUARTER TO ONE" instead of the less grammatically correct "IT IS QUARTER TO ONE".

Just some thoughts.

Best Wishes!

3 replies
DIY Machinesmaewert

Reply 1 year ago

Thanks Maewert. All your comments are perfectly correct. Forgetting to light the 'MINUTES' and 'O'CLOCK' was just forgetfulness when I wrote the programme out. I'll add them in unless someone beats me too it on Github.

DIY Machinesleon.gates.52

Reply 1 year ago

I think so. As long as you have a 3D printer there is only a few wires to solder and some gluing to do.


1 year ago


I made the smallest in the world one.... 8x8 3mm LEDs matrix some time ago.