Introduction: Wood Veneer Word Clock
What another word clock? There are already 100+ on instructables!
Most of them focus on the electronics part, this one is all about the execution: To make it a perfect looking, well designed and finished product, that one would buy in a store, rather than a hobby project to learn to work with arduino.
This is where this clock stands out:
- Nice look of real wood
- antique design as if it were designed years ago
- minimum amount of letters to increase readability
- Thin design; only 21 mm
- As simple electronics as possible
- birthday function
Material wise, the only thing I did not buy and may be hard to source is some nice wood veneer. Lucky for me, my father had some of this very nice veneer slabs that are almost 1 mm thick lying in his garage for many years. And this teak veneer is what makes this clock stand out. To cut the letters you'll also need access to a laser cutter, luckily, there are many fablabs, makerspaces and even companies that can help you out. Thank you Makerspace De Prins!
- 6 mm MDF; 3 pieces of 55 x 55 cm
- 3 mm plywood; also 55 x 55 cm
- thin metal plate of 35 X 35 cm
- 4 m LED strip with addressable Ws2812b LED's RGBW 30 Leds per meter DC5V as for example this one
- Arduino nano with Atmega328P chipset or preferably a nano every, in case you want to experiment with special effects
- Real Time Clock Memory Module DS3231 as for example this one
- Resistor of 330 ohm
- Capacitator of 1000 uF
- Resin suitable for casting
- Many generic small things as wires, glue, tape, buttons, varnish ... too many to list here
Step 1: Designing the Clockface
First things first; we start with what makes this clock special: the clockface. The size of this clock is determined by the size of available Ws2812b LED strips. I did use a strip with 30 LED's per meter, the widest readily available size, which will give a clock of about 50x50 cm, with minimal amount of soldering.
The first fun job is to design the order of the letters. I prefer to keep the amount of letters low to maintain readability of the clock. I believe that 11x10 letters is the ideal size. In one clock I made, I was not only able to put all the hours in full, but also all the 4 names of our family (including Kathleen which is pretty long) to lit up at their birthdays. In the other clock I made, as a wedding gift for my brother, I was able to include the names of bride and groom as well as the wedding date. Unfortunately he had to postpone the wedding because of the corona-virus lock down, so I'm a little stuck with a clock with a wrong date. So spend a night in front of your computer to puzzle the right order of letters for your clock. All other things are fixable afterwards, but not the order of the letters!
Another big issue is the design of the letters itself. Most word clocks, as for example this one, use a font where all inside areas from letters as 'O, A, D, P;...' are connected with the outside to prevent them from falling inside the laser. I really dislike this, in my opinion this ruins the look of the end result. I found a way out of this, it's more laborious, but anything for a magnificent end result!
Step 2: Manufacturing the Clockface
Back to the manual labour. At first we have to veneer one of the 55x55 cm veneer boards, as my veneer was less than 40 cm wide I opted for a picture frame style with a center part including all the letters, surrounded by a veneer frame in bookmark style. If you have access to a laser cutter (you'll need for cutting the letters anyway); these veneers are super easy to cut and super precise. I included the necessary SVG files below. They are a little oversize, but in that way they are easy to cut flush with an utility knife afterwards. I do not have a picture of the veneering step, but it's just a matter of glue, a lot of clamps and some patience. If it's your first time, watch some youtube movies and you'll be fine.
Now it's time to cut the letters. You definitely need a laser cutter for this job. Luckily I have a makerspace in my neighborhood; thank you makerspace de Prins! I prefer to put the veneer on the bottomside, to preserve all the detail in the letters. Of course don't forget to mirror your clockface; else you'll end up with an unusable clockface. To prevent burn marks on my veneer I did cover the whole veneer with masking tape, as can be seen on the picture. Also do not forget to collect all pieces that dropped inside the laser, as we will need them afterwards! Actually we only need the insides of all open letters; the letters themselves are cool to reuse for another project.
Step 3: Filling the Letters With Polyester Resin
Before we can fill up the letters we have to close the voids with tape. Use a strong adhesive tape as it serves 2 purposes:
- prevent leakage of the resin
- reposition the inner parts
So after taping the back side you can flip the face plate. Now you have to reposition all the inner sides of the open letters (O, D, ...). So you'll need a strong tape to keep them from floating around. Now it's time for pouring the resin. Don't jump too fast into this job. First make some try-out mixes to ensure that the resin color is nice, not translucent anymore to avoid a black hole effect, but not too opaque to block all the light from the LED's. To render the resin a little opaque I did mix it with some white spray paint, but there exist dedicated additives as well. Only use some drops, it becomes too opaque very soon.
Especially for the open letters, I did fill the letters in two layers. This gives you some control over the inner sides; once this layer is cured somewhat you can pour the second layer with confidence that they will not move around anymore.
The polyester resin I did use, actually was a bad choice. It cures too fast, so I had to make different batches increasing the risk of color differences. It also reduces the time to remove air bubbles. So a slower curing epoxy resin would have fixed both problems at once. You can make a single batch and get rid of bubbles by torching.
Step 4: Sanding the Faceplate
Now you're happy to have a thick veneer, so we can sand the letters easily flush. Nevertheless be sure not to put too much pressure in a single spot, because once you sand trough there is no way back. Looking at the back side of the letters, you can try to pour the resin from the back part to minimize the sanding; especially useful when you do not have such a thick veneer layer.
After sanding the front, I noticed many small air bubbles in some letters. They are very noticeable, especially now they're filled with sanding dust. To fix this I did clean the holes individually with a very small drill and filled the them with some dental light-curing resin (guess my profession!). And after some more sanding, it's close to perfect!
Step 5: Use a Router to Make Some Recesses
The letters on the faceplate are relatively big compared to the single led we use. To ensure a more uniform lightning and increase translucency I did cut a 3mm recess at every letter. This increases the distance from the LED to the resin, which defocused the light somewhat and because the resin is thinner, the light passes easier. You should adjust this depth somewhat depending the opacity of your specific resin mix, so try it out with some LED (for example from your cell phone) to guess what's best in your case.
Step 6: Assembling the Clock
Assembling the clock is super easy: use the laser cutter to cut the spacer plates from a 6 mm thick MDF plate and use some wood glue to bond them together. First glue the plate with the holes for the individual leds to the front plate and next the 4 spacers that will provide space for the metal plate with all the LEDS. Before glueing everything together I did use some spray paint to mark the position of the boxes on the metal plate. This will be helpful later for positioning the LED's on the metal plate.
Tip: For the metal plate I did use the case of an old broken CD player, reusing materials is better for our planet and our wallet!
For the backplate I did use a square sheet of thin plywood (3mm) and attached it with screws so it can be opened at any time. This works fine, but next time I would laser cut the back plate as well so that only the inner side is removable. This would make veneering the sides much easier and there will be no gaps on the sides. I attached plans for this modification below.
Step 7: Veneering the Sides
Now the clock is almost finished. Rectify the sides with a track saw or even better a table saw. If you have none of these, you may get away with some sanding. Now it's time to a veneer the sides. Cut some strips from the wood veneer and use wood glue and masking tape to fix the veneer. The only thing you have to be careful about is not to glue all sides at once, because it will render your clock inaccessible. So after glueing each side, carefully cut the back plate from the clock itself using a sharp utility knife.
Now all the wood work is performed, it's the good moment to apply some finish to your clock to protect your precious work. Usually I prefer some oil based finishes, but I'm afraid of gloss differences between the polyester and wood parts, so for this clock I did go for some strong varnish that covers everything. The result is very nice and glossy, but because of that hard to make nice pictures of it.
Step 8: Soldering the LED's
Now it's time to heat up your soldering gun!
Best is to start with the LED's. Positioning the LEDS is easy; just glue them in the middle of the boxes on the metal plate. But beware these Ws2812b LED's have a certain direction so start with glueing a LED at the position of the first letter. Now the arrows on the strip need to follow the natural order of the letters. So at the end of each row you have to run a wire from the Dout to the Din from the first letter from the next row. Other matrices often use a snake pattern, because it's a little easier, but programming the clock will be easier later on this way. Once finished soldering the LED's, attach the metal plate with some screws in position. Now is also a good moment to hook up the LED's to an arduino on a bread board; run the Neopixel strandtest, to check al connections and admire your clock for the first time!
Step 9: Adding the Electronic Components
On the picture the wires look very messy and complex. However there are only 5 components connected to our arduino nano. All of them are connected as in most tutorials and library examples, so if you never used them before have a look there.
DC power input: This one is very easy
- negative pole to the GND (ground) of the arduino
- positive (+ 5V DC) to the 5V or Vin and to the + of the LED strip
RTC (real time clock) DS3231: 4 pins are connected to the arduino directly
- VCC to 5V
- GND to GND of arduino
- SDA to A4
- SCL to A5
WS2812 led strip: Positive and negative are already directly connected to the power
- the Din of the first LED/letter is connected to the D6 pin of the arduino, not directly but over a 330 ohm resistor
capacitator of 1000 uF: This is to protect the LED's, probably works fine without
- positive leg is connected to the positive side of the LED strip (and therefore also the DC jack)
- negative leg is connected to the minus side of the LED strip (and therefore also the DC jack)
button module: I did use this 4 button module, but some simple momentary switches on a small piece of perforated prototyping board would do the job as well. As I do use the internal pull up function of the arduino, no additional pull-up or pull-down resistors are needed. So a wire from the switch to your arduino pin is all you need.
- one side of all switches is connected to the ground
- button 1 goes to D5 (mode button)
- button 2 goes to D4 (up button)
button 3 goes to D2 (down button)
Step 10: Software
The software was written using the Arduino IDE. As the configuration used is pretty standard, probably software you can find from other clocks can be used as well.
The software added below uses 3 buttons
a mode button for selecting the modes (normal, family names, screen off) and an up and down button for adjusting the brightness.
Long pressing enters the setting mode for adjusting time and date (used for the birthday function).
Of course you can use my software, but it's more fun and didactic to write your own. If you're creative you can come up with strange but funny things as playing snake on your clock. If you intend to do so, you'll quickly run into the memory borders of a regular 328P based arduino nano, so go for an arduino every or an ESP32 based controller that will even enable wireless controls, as playing snake with 2 buttons is possible, but not great fun.
Step 11: Adding Buttons and a DC Jack
Using a router you have to cut a slot that exactly fits your buttons. I did use a 4 button module, but I only use 3 of them; a mode button and an up and down button. It's a little scary to use a router so close to the edge; but the rule is measure twice, cut once and you'll be fine. Once you did cut the slot, you have to make some space for the wires and measure exactly the position of the buttons and drill some holes in the sides. I did reuse some cylindrical plastic filament from a toy as a buton and did trim it with some hot instrument so it can not drop out, but still engage the button underneath.
Now the final touch, adding a DC jack. This is the last and most easy job. Just drill a hole of the correct size, solder some wires and glue it in place.
Now sit back, relax and enjoy your work!
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