Introduction: Cryptic Calendar - With Encrypted Date Cards

About: Hello. My name's Arpan. At present, I'm an Aerospace engineering student. I love painting and making stuff.

Sometimes simple things can be made cooler with a few tweaks. Take this calendar for example. The text in the cards are encrypted, so nobody will understand it until you insert it into the decryption box.
I know, the date is not something anyone will want to encrypt. But this makes it way cooler than the boring calendar before. Inserting one encrypted card every morning to see the random boxes on the card get magically decrypted to that date will be so much fun. And it's very easy to make too! So let's get making!


Black paper


Punching machine (optional, you can use anything to make the holes)


Step 1: How Does This Encryption Work?

This was originally designed by Stuart Greer for the 2014 YCN Student awards. Although he hasn't shared how he made it or how it works, I found it really interesting and wanted to make one myself. So I started to design it on my own and realised that it is very simple.

There are grids of circular holes in the front face of the box. We have to make the black rectangles in the card in such a way as to hide the holes that don't contribute to the word we want to display. I will explain how to do that in a simple way in coming steps.

Each grid has 3 holes in the horizontal direction and 5 in the vertical direction. There are five such grids. Three for the month and two for the date.

So when you insert the date card, the holes that contain the black rectangles are covered because the decryption box is also black. The remaining holes display the date and month. It should be easier to understand as you read the building process ahead.

Step 2: Making the Decryption Box

Yes that's what I'm calling it. I think that sounds cool.
First I took a black chart paper and started making markings for the box. The dimensions are mentioned in the image above. The final box will be 10cm×10cm×5cm, with the top open.

Once the markings were done, I used a paper cutter to cut it out. Make sure to cut only around the order of the box and not to cut the folding lines. You can make lines on the faces that are not going to be a part of the box so that is easier to figure out which lines to cut along. Refer the images above to get an idea.

Once the cutting was done, I used a screwdriver to make creases along the folding lines. This helps the folds to be neat and perfect. Don't press too hard or you'll cut the paper instead of making a slight crease.

But before sticking the box, we need to make the decryption holes in the front.

Step 3: Making the Holes

Let me warn you, I did make a mistake at first. If you don't want to see what mistake made, and continue with the build instead, you can skip this step.

So as I mentioned earlier, there will be a set of 3×5 holes and there will be five of these sets on the front face of the box. Top three sets are for the month and the bottom two are for the date. To make the markings for the holes, I told a 10cm×10cm piece of white paper. My punch makes holes of 5mm diameter. So I drew pairs of lines 5mm apart for the holes and 2mm apart for the space between two consecutive holes. Then I drew the holes along the pairs of lines. After I finished drawing the 5 sets of 3×5 holes, I took the punching machine and started punching out the holes I drew. That I when I realised that i made a big mistake. The punching machine can only punch through the first two lines of holes. It doesn't have enough clearance to reach the next lines. I sat for a while trying to figure out a way, but there was only one option left. Cut out each of the 3×5 grids and make the holes on them. Then stick it back to the front face of the box.

Step 4: A Better Way to Do It

If you skipped the previous step, here's the summary in a sentence:
You can't punch all the holes using a double punching machine due to less clearance.

So I cut out 5 small rectangles of 25mm × 35mm and made three rows and five columns of holes using the punching machine. Make sure to align the holes properly so that they come in a straight line. They look pretty good I should say. I then made rectangular cuts of 23mm × 33mm on the front face of the box and stuck my 5 pieces of art behind them.

Then I closed the box and stuck it with adhesive. This completed the decryption box.

Step 5: Encrypting the Date

Now it's time to encrypt the date and month. Here's how to do it in a simple way.

First, take a 10cm × 10cm coloured paper. Now place it behind the front face of the box and hold it tight. Then take a pencil and trace out all the holes onto the paper. Make sure the paper doesn't move while you do this. Now remove the paper and cross out all the holes that make up the letters of the date and month. Your job now, is to make rectangles to cover the holes that are not crossed. As simple as that. Use a black marker to fill the rectangles. Your encrypted date card is ready! You can write the date and month on the empty part of the card so that you don't get confused when it gets lost in a pile of cards. Now insert it into your decryption box to see it magically display the date and month.

Step 6: Things That Can Be Improved

Now you can place the calendar on your desk and enjoy creating encrypted dates. You can also create encrypted messages behind the date card. Maybe it's your birthday or Christmas. You can keep a large number of cards inside the box because it has 5cm space inside. If you have a printer, you can make multiple date cards and print them out so every morning you can enjoy changing the dates.
If I would have to make any improvements, I would make separate cards for the month and date because the month doesn't change everyday. This should make the process of creating the cards easier.

Have fun!

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