Introduction: Sensor Animate Jack O' Lanterns

About: Hello ,I'm a French man who love the DIY. My goal, know how to built everything ...

(First sorry if there is some errors, my english is not perfect, i'm French).

Would you want to make a scary pumpkin ?

To make it live , with an environmental interaction ?

This is the good instructable for You !

We will see how to carve your pumking and bring it to life with the help of Arduino, PIR mouvement detector, servo-motors, LEDs and a MP3 player.

Step 1: Materials

We need for the carving part :

Big pumpkin

Small pumpkin (not really a pumpkin)

Feld Pen


Metal spoon

Wooden box (as big pumpkin stand)

We need for the hat and the tongue :

Red cloth

Dark cloth

Sewing machine (or your hand)

Sewing thread

9g Servo-motor for the tongue

Servo Hitec HS-785HB 3,5 turn (I had yet this one but you can use a traditional 180° Servo but you have to modify the servo values into the arduino code)

piece of wood


Dremel rotary tool

some Zip tie

Iron wire


We need for the electric / electronic part:

Arduino Uno

Computer power supply Unit (re use from old PC)

2 holes connected PCB + male/male connector

PIR sensor (Electronic Brick)

Relay bord

10x 10mm green LED (3,3v 90mA each)

4x 10mm green LED (2,3v 130mA each)

5x Transistors (3x BC547B and 2x TIP22)

Optocoupler 4N35

6x Resistors (4x 62ohm + 1x 22ohm + 1x 220ohm)

100uF condensator

Autonomus Strip LED

Cheaper Mp3 player

Portable speeker

Some Wires

2,54mm connectics

Heat shrink tube

Plastic clamp (Rislan)

Soldering equipement

Step 2: Carve It

Choose two good looking pumpking, one, big and one small.

For the big one :

Draw the patern directly on thepumpkin with a feld pen, wipe your draw or just a part if you want make it better

Remove the top cap with knife but keep it.

Take out the inside of the pumpkin with the spoon.

Use knife to cut your draw on the pumpkin. First cut it approximately with room and cut it perfectly in a second time, it's more easy to have a good cutting.

Drill a 1cm hole in each eyes to put the red LEDs inside

Cut a small hole in the back of the pumking

Put the pumpkin on the wooden box and identify where to saw the box to be in front of the pumking's bottom hole. Saw !

Make the teeth :

Draw the tooth

Cut along the line betwin the futur tooth and pumpkin skin, 3 milimeters deep.

Cut a notch betwin each tooth

Use the knife to « shave » the pumpkin skin on the tooth.

Make a gap betwin each tooth face with the peak of the knife.

For the small one :

The only difference it's to cut a hole on the back, not the top, and throw it away.

Step 3: Make the Hat

The hat is a simple dark cloth cone with a hem down :

Check the hat circumference and how high you want it on the head of the big pumpkin (circumference bigger than the top hole to hide it, but smaller than the pumpkin circumference to don't hide the eyes)

Fold in half the cloth and draw a triangle with a base large like the half of the circumference and high like you want your hat high + 3/4 centimeters of room for the Hem

Sew one side of the hat (the other don't need because the cloth is fold in half)

Return the cone on itself in order to hide the sewing inside

Push the room of cloth inside the cone and sew the hem

Cut a hole in the botom center of the hat in order to fix the PIR sensor

Cut the piece of wood to the wanted length, fix the servo-motor on the wood with plastic clamp

Fix the wood on the top of the big pumpkin, I cut a square to put the piece of wood inside lock by two small pieces of metal

Make a peak in cardboard and fix it to the servomoteur

(Length of wood + servo + cardboard peak is a little smaller than the hat height)

Step 4: Make the Tongue

Fold in half the red cloth and draw the tong along the fold (aprox.lenght :12centimeters, aprox. Width : 3 centimeters)


Cut the cloth exceed

Return the tong on itself in order to hide the sewing inside

Take an iron wire and wind it around a screwdriver in order to make a 12 centimeters spring.

Pass the spring through the servo head holes

Put the cloth tongue on the spring and fix it with plastic clamp (Rislan) or iron wire near the servo

Put a 100uF condensator on the PCB dedicate to this servo

Step 5: Make the Small Pumpkin 's Back

Draw the contour of the small pumpkin's back on plywood and cut it

Put the piece of plywood on the back of the small pumpkin, now see from the pumpkin's face and c identify with a feld pen where to fix the servo and the two red LEDs plus one hole for the Servo wire.

Make a split in the plywood in order to insert one servo's side fixation (I used a Dremel rotary tool because it's very fast and convenient)

Drill one small hole on each side of the servo in order to fix it with a plastic clamp.

Drill two one centimeter hole for the LEDs and one to take out the servo wire

Drill tiny holes around the plywood.

Use nails trought the tiny holes to fix the plywood on the pumpkin's back

Step 6: Hack the MP3 Player

Choose the cheaper MP3 player. We need to use electronically the play boutton:

Unscrew or unglue the face of the player , it depend of how your player is build.

Remove the play button, you will see under the PCB with a ring and inside a point

Solder a wire to the ring and one other on the point (don't need to identify which one)

Solder a push button betwin the two wires from the play button to the optocoupler, in order to be able to press « play » manualy (because the original button can't be re use)

I choosed to control only the play button to make it simpler.

So before to animate the pumpkin, i need to put manualy the MP3 player on Play mode and to put the level to max.

The probleme founded : MP3 player shut down after 1 minute and 45 secondes of no playing, so i write a code line to re activate the backscreen every time the code rolls one time.

I just upload one song on the MP3 Player : my homemade horror song.

The song is playing continuously so you just have to play at 0 seconde and to stop at 11,6 seconds (the end of my track)

Step 7: Electronic Part

It's an arduino Uno based project,

I make my own « proto shield » by cutting a 2 parts PCB and fix male/male connector (male/female connectors are better but i have yet the male/male one)

My PCB is not the most beautifull one, I re use it from an old project, it's why there is hole on.

All wire are solder and protect with heat shrink tube, I also use 2,54 mm connectors.

On my PCB you can see two octocouplers, the second was initialy for the button next song of the MP3 player but finaly don't use.


We power the system with a re-used computer power supply unit (12v and 5v)


All the LED are powered in 12V, so we need to drive them with transistor

I use one centimeter red LED (2,3v 130mA) and one centimeter green LED (3,3v 90mA)

I use 5 lines of LED with series connection, a resistor and a transistor on each line (see annexes)

Dont forget to put a paper with the line indication tape on each wire line, it is more easy to know where plug wire.

I use an autonomus strip led from an old display, with it own power supply.

I cut 2 parts of the strip and re solder with wires in order to put one small part in each big pumpkin eyes and the big part for the mouth.

I cut the mass wire and plug it on the relay module (you can use transistor but i have yet this module).

The relay module is power by the 5V arduino pin out, data on arduino 9


The Electronic Bricks PIR move detector is power in 5v, data on arduino pin 8

Control the play bouton :

I use a 4n35 optocoupler to contol the play bouton of the MP3 player through the two wires soldered on it. Don't forget to put a 220 Ohm resistor betwin arduino pin 13 and 4N35 pin 1

Air the music

For listen the music of the MP3 player, Connect it to a portable speeker

Step 8: Make the Sound Track

I used Audacity to make my sound track, with sound effects i caught on Youtube thanks to the free software « Atube catcher » (for video without copyright !)

Step 9: The Arduino Code

In order to make the code easier to write, I print lot of tiny pumkin on paper to draw on the base of lighting sketch.

The arduino code is in the annexes because it's too ugly to publish it here.

Download the .ino file and open it with the Arduino IDE

Step 10: Assembly

Put the two red LEDs in the pumpkin eyes's holes. Plug it

I order to separate each eyes of the big pumking, I used two small cardbord box drill for the green LEDs wire. I fix the boxes into the pumpkin with nails. Plug it on Arduino

Put the LEDs strip with the relay bord into the pumpkin. Plug it on Arduino

Plug the small pumpkin wires on Arduino

Put the portable speaker into the pumpkin,

Put MP3 player into the pumpkin, plug to arduino and to the speaker's jack cable

Take the player out trough the pumpkin mouth

Put the computer power supply unit in the wooden box, pass the wires trought the hole, into the pumpkin. Plug it on Arduino

Plug the PIR sensor and the hat servo on Arduino

Close the pumpkin's top, put the hat on the servo/cardbord peak and lock it with nails in the pumpkin

Take the Mp3 player, switch on, put the music level to MAX

Switch the speaker on

Replace the small pumpking in the big pumpking mouth

Turn on the power supply

Step 11: Enjoy

There is a waiting mode : just white lightening and every 30 seconds there is a small event, the big pumking red eyes blink or the hat move.

If PIR mouvement detector detect a human's (or animal's) mouvement, the pumpkin is activate, song track is play, light's colors change, hat and tongue move, folowing the song track scenario.

If you need more details contact me, i will answers.

Arnaud Dubreuil

Halloween Decor Contest 2016

Participated in the
Halloween Decor Contest 2016

Pumpkin Carving Contest 2016

Participated in the
Pumpkin Carving Contest 2016