Introduction: Secret Message Light Box

Picture of Secret Message Light Box

My 7th graders love to make things and we just got a 3D printer, so I came up with this light project. It's a small box with a design cut out from the inside, almost all the way through. When you shine a light from inside you see the design. When you turn it off, it's hidden! Cool!

Step 1: What You Need

Picture of What You Need

Here is the list of materials:
Of course first you will need a 3D printed box. I will not explain that in this Instructable, but I can say we used Tinkercad and made boxes about 40mm x 40mm x 30mm high, with 2mm sides, a 5mm bottom, and the shapes in the bottom cut down to make those areas 1mm thick. That lets a good strong light through nicely, while hiding it with no light.

To make the light switch:
2 pc. of cardboard, one 4" x 2", the other 2" x 2"
A 3v coin cell battery
A bright white LED
One red and one black wire, about 2" long
A Ping pong ball
Assorted Legos
Tape, masking is fine
Hot glue

Tools you will need:
Wire cutters/strippers
Scissors
Ruler
Basic soldering stuff

Step 2: Prepare the Base

Picture of Prepare the Base

Fold the smaller piece of cardboard in half. Cut a hole in the crease for the wire to go through. Now tape it on the longer piece so the open side faces away from the middle.

Step 3: Prepare the LED

Picture of Prepare the LED

Strip a small bit of insulation off of the ends of the wire. Solder the red wire to the longer leg of the LED and the black wire to the short leg. Melt a blob of solder onto the other end of the black wire. This will be the switch contact.

Step 4: Wire in the LED

Picture of Wire in the LED

Poke a hole through the top of the bent cardboard. Push the black wire through so the solder blob sticks out. You can bend it down a little to stay.

Put the red wire through the cut hole in the crease. Tape it down.

Bend the LED up close to the light, being careful not to bend it around too much or it could break off. Tape it down nice and flat with the LED sticking up.

Step 5: Attach the Battery

Picture of Attach the Battery

Put the battery with the flat side (+) down so it makes good contact with the red wire. Tape it down with tape only over half of it.

Now to test your switch! Push down on it until the solder blob touches the battery. Your LED should light up. The blob should just be touching the top of the battery, not the side.

Step 6: Add a Light Diffuser

Picture of Add a Light Diffuser

If you got a bright white LED it is very bright and shines on just a small area of your box. The light needs to get spread out. Cut the ping pong ball in half. Don't use an Exacto! It is much easier to use scissors, poking a hole first then cutting around the middle.

Hot glue a half ping pong ball over the LED. It will diffuse the light nicely.

Step 7: Make a Platform for the Box

Picture of Make a Platform for the Box

Legos work pretty well for making a platform for your box to rest on above the light. Just build one however you want and hot glue it down and for the final touch glue your box on it.

Also I realized you could just glue the box right on the ball!

Step 8: Enjoy!

Now you have made a cool piece of electronics! People will love to see what is revealed when you press the switch. Enjoy!

Comments

margaret.aiken (author)2014-11-11

How long does it take your 7th graders to make one of these boxes?

tmartin37 (author)2014-03-06

Nice!

About This Instructable

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Bio: Educational Technologist at The Hewitt School
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