Scary Doll Behind Fake Mirror for Halloween

Arduino beginners friendly! I had this idea in my mind for a while, and with Halloween approaching I decided to finally learn the basics of Arduino and make this project.

It's a box with a mirror in the front. You hear a buzzing sound, like one of a broken florescent tube. The light flickers. What is this box anyway? Let's get closer. As you get real close, a light suddenly flashes from inside the box. You now see what's inside: you're facing a creepy doll hanging upside down, with a horrible sound. You step back in fear, and it disappears.

The box:

1. Some wood (I used only wood from reclaimed pallets)
2. Paint (I used black and red)
3. some screws
4. a glass
5. one-way mirror film
6. red plastic film
7. parchment paper
8. a makeup doll

The electronics:

1. Arduino (and Arduino starter kit for prototyping)
2. 5V power supply
3. 2x 5V LED strip
4. 2x LED driver
5. Distance sensor (HC-SR04)
6. Wires
7. Cable connectors (only needed if you want to avoid soldering as much as possible)
8. Passive buzzer

Tools:

1. Soldering equipment:
2. Soldering iron
3. Solder remover (not mandatory, but recommended to recover from mistakes)
4. Solder sucker (not mandatory, but recommended to recover from mistakes)
5. Soldering fume extractor (not mandatory but recommended for your health)
6. Perfboard (not mandatory, but makes it easier to solder wires together)
7. Helping hands (not mandatory but strongly recommended if you do this project without help)
8. Solder paste (not mandatory)
9. Tip cleaner
10. Woodworking equipment:
11. Saw
12. Drill
13. Screwdriver
14. Wood glue

I got this doll from the recycling center, and made a few random changes: I burnt its face a little, and applied some paint. Not much effort is needed as it will not be visible very clearly inside the box.

Apply the one-way mirror film on the glass, and use it as base for sizing your box. Verify that your doll fits inside.

Assemble planks together to form a box and make sure that the glass is tightened, and in the right direction (otherwise the one-way mirror won't work).

Behind the mirror at its base, add a piece of plank of the same length as the mirror. This will serve to hide the LED strip that will be positioned there.

This is my prototype board. Notice that it used normal LEDs and not yet the LED strips. It therefore doesn't require an external power supply. This step is not mandatory if you know what you're doing, but it's always good to see the system work before you go further.

You'll have to import the EasyUltrasonic.h library.

Upload the code attached to the Arduino. I'm not a programmer so please excuse the quality. I know it could be a lot better.

There is code for:

1. various flickering lights patterns to mimic a florescent tube
2. buzzing and electric sounds to mimic a florescent tube
3. scary sounds

Place your components on the box:

1. 1 LED strip outside, above the mirror and facing horizontal
2. 1 LED strip inside, behind the mirror at its base and facing up
3. The distance sensor above the mirror
4. The buzzer somewhere above the box

Once the components are placed, you can measure the length of your wires. Cut them to the right size and proceed with connections and soldering.

The final version of the circuit is the same as the prototype board, except I replaced the 2 LEDs and their resistor by 5V LED strips and an LED driver because the LED strips require more power than an Arduino board can handle. I also replaced the Arduino Uno by the Arduino nano. And it's now powered directly from a 5V power supply instead of the USB.

The power supply positive wire must:

1. Be connected to the Arduino 5V pin
2. Be connected to the LED drivers VCC pin without going through the Arduino

The power supply ground must be connected to the Arduino ground pin.

I stapled the parchment paper over the LED strip to make it more diffuse and resemble more a florescent light. Then I applied the remaining of black and red paint that was still on my brush in order to give it an "old and used" effect.

I also stapled the red plastic film over the LED strip inside the box.

Tidy all wires inside, secure the electronics in a small plastic bag.

If you like, place the doll upside down for a better surprise.

You can now close the back of the box. Ideally with magnets so you can open it easily if needed.

Now place it outside, with a bowl of candy just in front of the mirror.