This year I thought I would bring one of my favourite childhood Halloween characters and her best friend to life with my Meg and Mog flying pumpkins experience.

I was inspired to go a little further than my usual Halloween creations that my son always asks for, by the pumpkin carving competition on Instructables. For this project I used three pumpkins which when placed on different levels, spaced apart and then illuminated sequentially with LEDs controlled by an Arduino Uno, give the effect of Meg and Mog flying up, up and away....!

Step 1: Things I Used for Materials and Tools

3 x pumpkins

1 x bucket for pumpkin bits and seeds

1 x spoon to scrap out seeds etc from inside of pumpkin

1 x narrow blade knife for pumpkin carving

1 x cordless drill and small drill bit for small details or areas that are weak

1 x cloth to wipe up and keep big mess under control as I went

1 x print of my image to carve

1 x square of baking paper for tracing

1 x Arduino Uno

3 x 1m of old phone cable

3 x small circuit breadboards

6 x LEDs

1 x 4xAA battery holder with plug

4 x AA rechargeable batteries

1 x small plastic bag to waterproof my control board

3 x wooden posts to support pumpkins

3 x scrap of wood for the top of each post

3 x nail to affix scrap of wood to post

1 x camera to take pictures

1 x computer to write Arduino code etc.

Step 2: Transferring Image Onto the Pumpkins

Firstly I found an image that was simple enough to carve and that could easily be mirrored and would still look good just as an outline. I would like to thank Helen Nicoll and Jan Pieńkowski for the creation of such cool characters. I printed the image in black and white and then traced onto some baking paper using a pencil. I then laid that tracing over the pumpkin and retraced the outline onto the pumpkin leaving a very faint imprint which I could follow to carve.

Step 3: Carving the Pumpkins

Once the design is marked out on your pumpkin you can begin carving.

I cut the bottom out of the pumpkin not the top, as this tends to let the pumpkin hold its shape for a little longer as the top seems to shrink and collapse over time. Because I am using LEDs for illumination I didn't need a hole in the top at all but if you are using candles you would need a small hole to let the heat out and for air circulation.

A knife with a narrow blade is best for pumpkin carving as it is easier to navigate around corners. I also used a drill with a small bit for the details that were very close together; a Dremel would be the ideal tool for this job ;-) but i don't have one :-(

Two of the pumpkins were carved with the image the same way around and the third Meg and Mog on the broom were mirrored. I took nearly two hours to carve the first one but the next two took around 45mins.

Step 4: Illumination Circuit

For the illumination I used an Arduino UNO and three small bread boards with two LEDs on each. The small breadboards with the two LEDs were then connected with some old phone cable and placed inside the pumpkins. I programmed the the Arduino to flash the LEDs in sequence from bottom to top in a loop. Using the code below you can vary the on time of each LED and the delay between each. I played around with this until it looked realistic, not that I really know what it is like to see Meg and Mog fly around my garden on a broomstick. I used 'Autodesk Circuit' to draw the circuit as shown in the attached picture and to simulate the circuit as shown in the video to prove the code before uploading to the micro-controller. I powered the board and LEDs with a 4 x AA battery pack plugged into the external power supply socket. Using 4 x AA batteries is a better option than using a single 9v battery as it is more efficient and has more capacity as well as being cheaper. I fastened the control board and battery pack to a small piece of wood and put into a plastic bag to waterproof.

Arduino Code:

int led1 = 13;

int led2 = 12;

int led3 = 11;

// the setup routine runs only once, and each time you press reset.

void setup() {

// initialise the digital pin as an output.

pinMode(led1, OUTPUT);

pinMode(led2, OUTPUT);

pinMode(led3, OUTPUT);

}

// the loop routine runs ensuring the program cycles from beginning to end ad infinitum.

void loop() {

digitalWrite(led1, HIGH); // turn LED1 on

delay(500); // wait for a set time period

digitalWrite(led1, LOW); // turn the LED off

delay(10); // wait for a set time period

// and repeat for the next two LEDs

digitalWrite(led2, HIGH);

delay(500);

digitalWrite(led2, LOW);

delay(10);

digitalWrite(led3, HIGH);

delay(500);

digitalWrite(led3, LOW);

delay(10);

}

Step 5: Final Positioning

I hammered three wooden posts into the ground and with a single nail fastened an old scrap of wood to the top of each. On these I then placed the pumpkin 'corks' on top of which I sat the bread board with LEDs. I then placed the carved pumpkins on top of these, tested the circuit and then waited for the sun to go down.

I have to say, that although this does look cool on the video, in total darkness in my garden the affect was awesome and really brought a smile to my face and made my son jump for joy :-) so a project worth doing.