Introduction: Bloody Mary's Mirror: It Breaks When You Look at It!

About: A 22 year old Engineering student from Spain that loves anything related to engineering and just creating in general: from props, to electronics, to 3D printed parts.

One of the most recognisable scenes of paranormal and scary movies is one where the main character looks into a mirror, only for that mirror to instantly shatter and break. In this Instructable, we will show you the process that we followed to make such an effect so that you can use it this Halloween.

We are Alex Latorre and Quim Gutiérrez, two Third Year Design Engineering students in ELISAVA, in Barcelona. For one of our classes, we were tasked with creating a product that could be used for this very spooky Halloween season. We will give you all the instructions to recreate this very recognisable piece of film and horror scenes.


To make the mirror we needed the following materials:

- Mirror Vinyl (210x297x3)

- 2 Wood plank (297x420x30)

- PLA Filament (About 20g)

- 2 transparent sheet PMMA (210x297x3)

- Diffusing light material

- 1 opaque PMMA

- Spray Paint: Black, Brown and Silver

- Glue

- Arduino Nano

- DHT UltraSonic Senser

- Rechargeable Battery (2500mA)

- 6 Blue LEDs

- 220Ω Resistors (6 units)

- 1KΩ Resistor (1 unit)

- 1 Speaker

- DFPlayer Mini Module

- Screws M4 (4 units)

Step 1: Designing the Frame

Knowing all the elements and things that we wanted to include, we started to create a 3D sketch of our mirror. We designed it using Fusion360.

There are different ways to design and make the frame (the easiest being to just buy a commercially available one). We wanted to take the most advantage of the tools and resources available in our university: namely a CNC. To use this machine, we needed our 3D document to be in .obj format. Once we had designed all the parts, the sent it to our workshop so that they could use their CNC on 2 planks of MDF.

Step 2: Making the Glass

Step 2 is about how to make the mirror and all its parts.

The mirror is made up of 4 parts or layers.

  1. First we will cut the two transparent PMMA sheets with approximate dimensions of a DINA 4; we will repeat the process with the light diffusing material and the opaque PMMA.
  2. Then, with great care, the broken pattern is made by breaking the opaque PMMA sheet, and we will glue the resulting pieces on one of the transparent sheets.
  3. With the other transparent sheet, we covered it with the mirror vinyl using a little soapy water.

Finally we will join all the layers with glue in the following order:

  1. Mirror
  2. Pattern that we have generated simulating a break
  3. 3. the light diffusing layer.

Step 3: Decorations, Painting and Finishes

To place the mirror in a spooky setting and make it even darker and grittier, a series of decorations were made. These were modelled in 3D and printed with a 3D printer (Ender 3). Again this process depends on the setting you want to give.

With all the pieces ready, they were ready to paint them. The decorations were painted with silver spray while the combination of black and dark brown was used for the frame. Finally we attached the decorations to the frame with glue and with the help of some metallic element we made some marks to make the most ancient and terrifying mirror look like.

Step 4: Electronics

At this point of the project we take care of the electronic part. To make it easier for you to understand all the connections that were made, we attach some images of the Arduino circuit made with Tinkercad.

Step 5: Programming

To better understand how we were going to program this project, we first created a flow diagram. After doing that, we wrote the code. This code is included in this section (called Halloween_Mirror.ino).

Step 6: Final Assembly

To join all the components together, we first inserted all the electronic components and secured them in place. After that, we placed the mirror assembly inside and finally screwed everything together with 4 M3x25 screws.

With that, our Bloody Mary Mirror is complete!

Step 7: See It in Action!

Step 8: Conclusion

As we have seen, making Hollywood level decorations and effects isn't that difficult to make. From this project, we have learned to seamlessly integrate electronics and Arduino into any project. We have thoroughly enjoyed the process.

We hope you have enjoyed reading this Instructable and that you try to make it yourself!

Happy Halloween and see you in the next project! :)

Halloween Contest

Participated in the
Halloween Contest