In this article I have something stylish for you: It’s a project idea, I had for a while. And today I decided to finally build it! I’m pretty sure almost everyone of you has already seen a world clock, even if most of you have just seen them on pictures. For everyone else: It’s one of these clever clocks that do not display the exact time, but display a sentence, approximating the time instead, composed from different words that light up:
As these clocks can be pretty expensive, I decided to build some cheap ones myself. Three of them will be given to two friends of mine and one is for me. This article will be a description of the steps needed to create such a thing, so you can build your own one at home!
Before even starting to do anything else, you have to think about the materials you want to use. I want mine to be modern looking with a stylish finish, so I decided to go for a case made out of wood. The front of the case will be made of a polycarbonate piece with the letters printed on.
After I decided to go for certain materials, I had to think about the layout for the letters on the front. I decided to create a 12 by 12 pattern. To be honest, I simply wrote some letters into an empty text document and added each of the twelve numbers and other phrases to it. I came up with the layout seen in figure 2. The layout I’ll use is in german, but it should not be a problem to exchange the important words with their english counterparts. The other letters, which can light up, but don’t form any words, are displayed in black. They are gibberish only, so they do not need to be translated, but you can exchange them with other letter, if you want to. As you can see, I used a monospace font, however the layout I created was too high, so I needed to create an image that can later be used in the manufacturing process of the front plate. So I started up Photoshop and just copy-pasted in the text, you see in figure 2. I resized the letters and reduced the space between the lines. I ended up with the black and white design (see figure 3), which I printed out later and used it as a template for the letters on the front panel of the finished clock:
After these very basic things are out of the way, you have to think about the size of the clock. What size do you want it to be when it’s finished?
I wanted a rather compact one, so I decided to go for 26 by 27 cm (this is the size of the front panel, but there is an extra 1 cm on each side for the frame, so the total width is 28cm and the height is 29cm). Why did I choose this format? Well mostly because it fits perfectly onto a sheet of A4 paper, which makes printing it out and aligning it on the front cover way easier. My second thought was to make a compact and light clock that doesn’t occupy a lot of space on a wall, but is still easily readable. I decided to go for a clock sized 26 by 27 cm (this is the size of the front panel, but there is an extra 1 cm on each side for the frame, so the total width is 28cm and the height is 29cm) instead.
Planning user interactions
You should also think about how a user (e.g. you) can set the time of the clock and if it is possible to turn it off or not. Also think about all the features (like standby, other displays, etc.) you want to include NOW. Including these things later in the project might not be easy. If you are undecided about your clock’s features, leave at least some space in the case of the clock, so you can easily add more things later. But it’s a good idea to think about them now and write them down, so you don’t forget anything. My feature list is:
Turn the LEDs off. Might be useful if you are on a vacation or if the LEDs are too bright in the night.
Set hour and minute
- Change mode
A feature I plan to add later, where different display modes are available.
- LED controls
Select LED brightness and color
- Night mode
Automatically dim the brightness of the LEDs with a light sensor.
Sorting out the electronics
After you sorted out the size, the shape, the material and the functions of the clock you want to build, the time has come to think about the electronics to use in the build. We’ll take a look at the electronics in the next part of this series, but you should start thinking about it now. What colour should the LEDs be? How do you want to control them? Is your clock battery powered or not?
Think about the case and design
Now you have to think about how you plan to assemble the clock. How to fit the parts together and how to take them apart in case you need to repair or change something. My setup is shown below, where the single pieces of wood are laid out but are not glued together yet:
Note that the “not so nice” parts in the center will not be visible in the finished clock. They only serve as spacers to hold the front plate and the back plate in place, so they are made out of excess wood, which is the reason why they are so uneven. I might fix that in the other clocks, but as this one is for me, I’m fine with it.
The front plate made out of plastic will be glued on the spacers in the front of the clock. the spacers will be in the center, glued to the frame pieces on the side and to the front place. The LEDs will sit on a PCB I’m going to show in the next part. This PCB will be screwed down onto the spacers from the back. Between the front-plate and the PCB there will be a grid made out of foam. This will guide the light from one LED to the correct letter on the front, so that only the correct one lights up, if a LED does. Behind the PCB there will be all the wiring and everything is closed up with the back plate, which will be screwed down as well, so I can open up the case easily, if I have to change anything.
About the front plate
Currently I plan to buy a 5mm strong sheet of plexiglass and cut it to the right size. The letters (see fig. 3) will be printed on a sheet of paper and then I’ll cut them out of a black sheet of paper which I plan to simple place behind the glass. This is the cheapest possible way of making this.
If you are willing to invest a bit more and if you want to go with the professional finish, you can order custom printed glass panels online and get them delivered.
However that might be quite expensive, so I’ll try my cheap method for the first prototype.
So these are all my ideas. At this point I’m not sure how all of this is going to work out. However I’ll keep this section as it is, just to document the whole process of planning and building such a thing, so that you can learn of errors I eventually make during the process and so that I can review the process myself when I’m done with this build. However if something changes in my setup, I’ll update you.
See you in the next part, where we’ll take a look at the electronics and how I planned to build it.
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