I wanted a dual time zone clock in my lab/shack area and found these 24 hour led clock modules on eBay that go for about $5-$9 a piece. There are various styles out there, most of the lower cost ones are red LEDs, I went with a yellow color. When searching for these clocks, they sell both built, and un-built kits so be aware of which ones you are interested in. If you do go with a kit, be sure it can fit into the altoids tin once it is built. I choose a prebuilt clock. They also come in different voltage requirements. I went with a 12V (vs the majority found are 5V) model. I wanted 12V so I can easily tap into my power supply that powers various radios in my shack without any additional components. The two clocks I purchased were advertised as .56" in height, which works great for this project. I also had some extra grey tinted .118" acrylic I had purchased for another project to give it a better look.
What you'll need
- 2 24 hour clocks (kits or pre-built) from ebay (~ .56" in height)
- .118" or similar tinted cast acrylic sheet (grey)
- 2.1mm coaxial DC jack (or something else you may have laying around to connect up the power)
- Misc Tools - Hot Glue Gun, Hole punch, metel hand nibbler, scoring device to score/snap the acrylic to size, ruler, soldering iron
- Blue painter's tape, pencil
Here's a quick run down of the build...
I started with laying the clock down across the acrylic to mark up the sizes I needed to cut the two pieces needed as my faceplate.
Then I proceeded to use a scoring tool, to score a nice straight line into the acrylic. Using this method you don't "cut" the thin acrylic, you score it deep enough and break off the pieces needed.
One piece down to size, one more to go...
Here are both faceplate pieces completed, ready to be used as a guide to mark-up the altoids tin. The rough edges can be smoothed out with some light sanding. Be careful not to make contact with the face as you smooth out the edges. You can put the sandpaper onto a flat surface and run the piece across to ensure a nice even, straight edge.
I take a measurement of the faceplate, measure the width of the altoids tin, subtract the two, then divide that number by two, in order to find the edges to be able to center the openings for the clocks.
I double check my markings to see if everything lines up and looks accurate.
To create an opening, I find a standard paper hole punch works great when working with these altoid tins. You can use other methods as well, (sharp nail, awl, etc) just keep in mind, the metal is very thin and can crease or bend easily. You do not want to use a drill with this thin metal.
The altoids tin is no match for the hole punch. A nice clean hole. I punch a few of these to create a large enough opening for my metal nibbler.
Nibbling away...
Here's a shot of the opening partially completed. You can probably use other techniques to create a straight opening, but I haven't tried anything that is better than using the hand nibbler.
One down, one more to go. The metal is very thin, so I had to extra careful to not to damage it, especially in between where the two clocks will sit.
I insert the acrylic faceplate into the new opening, ensuring the front is semi flush and straight. I then proceed to run a bead of hot glue around the back edge. You can use your fingernail and a little alcohol to help remove anything you may get on the face of the acrylic once it dries.
Here's a view from the front once both faceplates are hot-glued in place.
Next, I lay in the clock units, carefully aligning them to their faceplates, and hot glueing them in place.
I punch another few holes large enough for DC power jack to be mounted on the side and solder up the red and black wires. Double check where to mount the DC jack, that there will be enough room for the lid to close properly. You can use a little bit of heat shrink or some electrical tape to prevent any shorts.
You can see in this angle how easily the metal can crease as you work with it.
Apply power and your done! The other wires you see, get stuffed into the tin. These are attched to tiny push button switches in order to set the time.
One thing I'd like to add with this project, even though you set the time to each clock, they tend to drift a little, so over time, you may notice the minutes be off from one another. If you're really adventurous, you can probably poke around the micro to try to sync both of them together, but I'm satisfied with the end result.
