Parts and Crafts is a non-profit family hackerspace in Somerville Massachusetts. We teach kids to tinker, make and play with electronics, crafts, carpentry, computer programming and more. We've developed a series of projects that can be made by and with kids, using readily available materials and supplies. We have launched a Kickstarter to sell these projects as kit subscriptions that we manufacture ourselves, but all of our projects are open hardware, so the instructions about how to make them are available for anyone to use! We plan to make videos, online instructions and instructables about all of our projects.

What is an infinity mirror? An infinity mirror is a pair of parallel mirrors which create a series of smaller and smaller reflections that appear to recede into an infinite distance. We can make one using a strand of LEDs, a power source, a cardboard tube and two small round mirrors, one out of acrylic and one out of “one way mirror” film used on car windows.

This is a very simple infinity mirror, designed to be build by kids or grownups that are new to electronics. It's based on one of our kits so the pictures show crimp on connectors in the circuit, but you can also simply solder or twist-and-tape the wires (I'll explain how when we get to that step.)

Parts list:

1) A very short length of cardboard tube (the inside cardboard from a used-up roll of duct tape works well.

2) A switched AA battery pack with leads. (We love the ones from TeacherGeek.com, cheap and sturdy, but any will do: https://teachergeek.com/collections/bulk-component...)

3) A short strand of LEDs (about 8" long for a 3" diameter tube.) You can solder your own strand together or pull out and re-purpose the strand from a cheap light up toy like this: http://www.rinovelty.com/ProductDetail/glswogr_28s...

4) Two AA batteries

5) A small round mirror. We use thin acrylic mirror and cut it into circles on the bandsaw, but there's no reason you couldn't use glass, especially if you found one the right size.

6) One way mirror window film. There are lots of places to get this. Unfortunately it usually comes in large rolls and you only need a small piece, but it's available on amazon and more other major retailers. Here's one example: https://www.amazon.com/One-Way-Mirror-Film-30/dp/B...

7) Electrical tape and scissors

8) Hot glue (optional, but useful)

9) Soldering iron and solder if you want to solder your connections.

10) A sharpie marker (for tracing your circle.)

Step 1: Prepare Your Materials

Cardboard tube

First paint the inside of your cardboard tube (especially if it's the inside of a roll of duct tape, with branding on it.) We usually paint ours black, but if you paint it with several coats of white paint, that also creates a nice effect. Jab two holes in the side for the wires to come out - you can use a drill for this if you have one, or just stab and cut with an x-acto blade or similar.

Backing Mirror

We use thin acrylic mirror, trace the tube shape onto it with sharpie and cut out the circle using the band saw in our shop. However, round acrylic and glass mirrors are available at crafts stores and online if you don't have a bandsaw.

Step 2: Build Your Circuit

Take your strand of LEDS and put it inside your tube. Then push each end of the LED strand through the holes, from the inside OUT of your tube. You want your strand to be trapped inside the tube with the connector ends outside. The pictures show crimped on connectors, but you can also simply push the legs of the last LED in your strand through the holes.

Now put batteries in your battery pack. (We like to remind kids to put batteries in "flat side against the spring.") On the battery packs we use, when the metal lever is up, the pack is off, and when it's pushed down snugly, the battery pack is on. Remember not to let your black and red wire leads touch while the battery pack is on or your circuit will short and your batteries will overheat!

Step 3: Wire It Up!

In order to light up an LED strand with a battery pack, we need to connect the positive lead from the battery pack (the red wire) to the positive lead on the LED strand, and the negative lead on the battery pack (the black wire) to the negative lead on the LED strand. On a single LED, positive and negative are indicated by the length of the LED leg, however on our LED strand with crimp-on connectors, or on an LED strand that has been cut to fit the project it is impossible to determine that visually. Therefore in order to determine the “right way round” for our battery pack, we need to turn the battery pack on by pushing the little metal lever on the battery pack firmly down. and just touch one lead to one connector and one to the other. If the strand lights up, that is the correct configuration. If it doesn’t, we need to do it the other way around.

Once you've figured out which was to connect your wires, connect them! If you have crimp on connectors, push the flat end firmly into the slotted end. If you don't have crimp-on connectors, strip the wires with a wire stripper and then twist them together tightly. For a good, solder connection, you can solder them but in a pinch you can also just wrap them with electrical tape. For all connection types, it's a good idea to wrap each side of the connection separately with electrical tape to avoid accidentally short circuiting if the positive and negative connections touch.

Step 4: Secure Your LED Strand Inside the Tube

Now you can secure your LED strand inside the tube. For the best effect, you want it to be straight and even and as equidistant as possible between the back edge and front edge of the tube. In the photos I've used electrical tape to secure it, but this is a place where a few dabs of hot glue work well. Make sure your LED strand isn't twisted because that can also cause a short circuit.

Note: For illustration purposes, I have my LED strand turned on in this photos, but you can also do it while it's off. However, having it on is a good way to tell if the way you are securing it is causing it to short (because the LED strand will turn off, or flicker.)

Step 5: Add Your Backing Mirror

As explained, we use acrylic mirror cut into circles. It usually comes with a thin film protective coating, which it's important to remove, or else the resultant infinity mirror will look cloudy. If you're using glass or your acrylic mirror doesn't have a protective film, you can skip this step.

Now attach your mirror to your tube. It doesn't matter which side you put it on, but you must place it mirror side in. The mirror must face towards the LED strand, into the tube. In the photos I use electrical tape to attach my mirror, however this is another step where hot glue works well. However, try to avoid using too much or getting strands of hot glue across your mirror, as this will mar the final effect.

Step 6: Add Your Front Mirror

Trace the shape of your tube onto your piece of one way mirror film with a sharpie and cut it out. The final effect is greatly improved if this piece of window film remains as unwrinkled and debris-free as possible, so be careful!

Place it carefully onto the other side of your tube (the one without the acrylic mirror.) It does not matter which way this mirror film faces. In the photos, I'm using little pieces of electrical tape to secure it, but small careful dabs of hot glue would also work well here.

Step 7: Make It Your Own!

Your infinity mirror is now complete and should look very cool! You can glue or tape the battery back onto the back to make a little stand (make sure you can still access the switch), decorate the outside with tape, paint or glue on decorations, or use it at part of a costume, prop or art project. If you do something cool with this project, please be sure and let us know! And if you visit the greater Boston area, please come visit our family hackerspace and make something with us!