How to Halloween Skull and Bones

Did you watch some of the amazing Halloween props on Youtube? I did and was determined to create one of my own. I first wanted to create a halloween prop over a year ago, but the parts arrived late and I skipped last years Halloween.

This year I had plenty of time before Halloween arrived, so.....

When this project is finished, it will gently glow the eyes and play a happy song. When someone triggers the motion detector, the hand will point to the intruder, the volume will go up, the scary sound effects will play while the eyes blink violently. Once there is no more activity in front of the sensor, the hand will return and the device will go back to idle mode again!

This tutorials comes with all disclaimers, including but not limited to burning down your house and causing a heartattack on your grandmother...

Arduino Mega (or use a compatible clone)

Motion detector (also known as PIR sensor)

Servo motor

DFPlayer mini MP3 module

Micro SD card

Breadboard

Small speaker (2 Watt I think, quite small)

Some resistors (2x 330Ohm, 2x 1KOhm)

3*AA battery enclosure

9 volts powersupply for arduino

Wires

Bag of bones to your liking

Old cloth

Some leftover wood to build the project on

Soldering iron and solder

Some isolation tape (black)

Cut yourself a base from the leftover wood, mine is an oval about 50 cm by 20 cm. On the base you need to create a standing base in which to fit the servo motor. I attached two small pieces of wood to the base using angle brackets. I then inserted the servo in between the pieces of wood. I taped the top of the standing base (with the servo motor in it) with black tape to make it less visible. On the rotor of the servo motor I attached a thin piece of wood to apply the hand.

I drilled two holes in the eyes of the skull. I then attached two 40 cm wires to each of the red leds. The wires were then fed through the hole in the eye and the led was hot-glued in place. Through a third larger hole in the bottom I retrieved the led wires using a piece of electrical wire with a hook bend at the end.

Please have a look at the Fritzing image attached. If you are new to this, it may be a bit overwhelming at first. Just follow the wires and connect one by one to it's correct place in the scheme. It will take some time. The distance sensor to the right of the arduino should be a PIR sensor (requiring the same amount of wiring, check your sensor and / or the image for the correct wiring). The image lists a 2x AA power, but you probably need 3x AA to rotate the servo.

There is one file missing here as it is copyrighted. It is the file 0003halloween.mp3 which will be the idle tune playing when there is noone around. Please copy all the files (and your favorite idle song named 0003halloween.mp3) to a folder MP3 on the micro SD card. Insert the SD card to the DFPlayer's card reader.

Install the Arduino IDE software from arduino.cc. You will need to add the MP3 files as a library to the Arduino software (look at arduino.cc for instructions if neccesary).

Now attach a USB cable between the arduino and your PC, check on which COM port your Arduino is connected (and configure the Arduino software accordingly). Load the .ino file in the Arduino software and upload the file to the Arduino. It *should* start testing the different components:

1. Light up the eyes

2. Play a song

3. Rotate the servo motor back and forth

4. Calibrate the sensor (this will take 30 seconds, be patient)

Then it should loop idle until a kid triggers the motion sensor!!!

I had an old black (ideal for Halloween) cloth lying around. First lay down the cloth and place your project on top of it towards the back. Take the front of the cloth and wrap it over the project (but not the hand of course). Now place the skull on top of the cloth (keep the wires to the skull hidden) and locate the motion sensor in an appropriate place. Add some more bones to the project to your liking and power on your project.

Happy Halloween!!!

Originally I intended the head to be mounted on the servo motor. As my engineering skills aren't up to par, I ended up with a stationary head and moving hand. Feel free to place the skull on the servo motor for added effect.

I also had the idea to dress the result up with a t-shirt (this is why I have an oval base the size of a chest). Hanging by a few strands of clear wire, "floating" in mid-air with a rotating head and a few arm bones dangling would make the ultimate version, but alas.... May be in the future...