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So you have an unused LEGO Bucket and you want to turn it into a "scary" pumpkin head for Halloween. I didn't either, but I did have a fully involved LEGO bucket that I dumped out and decided to make into a "scary" pumpkin head. ;^)

I saw this LEGO Bucket, set 3047 from 1998, in amongst my LEGO collection and decided to turn it into a pumpkin head for Halloween. I placed two stipulations on myself for this, my first Instructable. First, I didn't want to ruin the container. Second, all of the electronic components had to be recycleable or reusable in some manner.  

I am happy to say I accomplished both. Follow these steps and you can turn practically any plastic Halloween bucket into a LED lit pumpkin head.

Step 1: Source the Parts

You must obtain basic electrical components for this build and a Halloween bucket. I used the previously mentioned LEGO 3047 Set - Halloween Bucket

The electrical components include the following but are basically a power source (battery holder), batteries, LED's, a resistor, and wire.
 
  • (2) 10 mm White, Ultra High Brightness LEDs (~23,000 mcd)
  • (6) 5 mm White, High brightness LED's (~2,300 mcd) 
  • (2) AA Batteries
  • (1) 10 ohm resistor
  • (1) 2 AA battery holder
  • wire of various lengths cut from a spool, I used 20 guage wire
Of course, I sourced all of these parts from Radio Shack. Some stores have what you need and others do not. I went to two separate stores and was able to obtain the parts I needed. I welcome comments from anyone that can suggest a better source for the price.

Step 2: Foam-core Is Our Friend

I also obtained foam-core, project board from a local retail store conveniently located in the same shopping complex as one of the Radio Shack stores I visited.

Cut the foam-core to a size that fits into your container. While mine was "square," you might find a round container in which case I suggest arranging the foam-core in a square or box shape. With the LEGO Bucket I needed only to tapper the sides as the bottom of the bucket was narrower than the top.

I cut 4 pieces. There are 2 supporting sides, the main face side, and a false bottom that would allow candy to be placed on top without interfering with the wires or the lit face.

Fortunately, due to the lip at the bottom of the LEGO bucket, the sides slide into the bucket and were "locked" in place by the bottom. With the face plate sliding in between the two sides, this anchored everything together and did not require a 4th side.

That's when I got the idea to use the fourth side to lay in the bottom and cover the wires and LEDs that were exposed on the back.

Inserting the LEDs into the foam-core was easy. I used an exacto-knife to cut an "X" in the spot where I wanted the LED. The "X's" were placed there after drawing out where I wanted the face to go.

I then used a pencil to poke a small hole through the cut portion of the foam-core. I then pressed the LED through the hole trying to stop at the lip around the LED acrylic housing. This resulted in a fairly stable, friction mount of the LED.

Step 3: Wire Up the LEDs

Okay, I am a complete novice and I impress myself that I even knew where to start, but the LEDs have a cathode and an anode side (lots of learning and reading Instructables to obtain this understanding). That means one is positive and one is negative. Not wanting to get into electron flow theory here, keep it simple and test first.

I started with one 10 mm LED in a breadboard and a bunch of resistors. I arranged the resistors to have different groups in the breadboard so that I could move a wire from one contact on the LED to different resistors. The resistors where in the Negative terminal bus and the other lead on the LED was wired up to the GRND on the breadboard. Of course, the negative of the battery holder (the red wire) was wired to the Negative bus on the breadboard and the GRND (the black wire) was wired to the GRND bus on the breadboard.

(If I have this screwed up, please correct me in the comments).

I plugged the LED into the board and used a wire to complete the circuit. I discovered it worked. This told me that the longer lead on the LED was connected to the Negative Bus (so that's anode, right?)

Anyway, I moved the wire from 10 ohm, to 100 ohm, to 150 ohm, to 1,100 ohm, to 2,300 ohm to determine the brightness level I wanted. The 10 ohm resulted in the brightest output from the LED.

Then I checked the other 10 mm LED. My initial idea was to connect these LEDs in series running from long lead to short lead. This did not work. Then I tried long lead to long lead, which did not work. That was no surprise because it shouldn't have worked.

I then tested the LEDs in parallel and everything worked. Please let me know in the comments section why I couldn't wire the LEDs in series but had to go with a parallel circuit. I could have spent hours working this out for myself, but I went with it as it worked.

In the photograph below you see that I have the LEDs inserted into the foam-core and wired up. I oriented all of the LEDs with the long lead on the outside of the circle and the short leads on the inside of the circle. This made wiring and soldering very simple.

I used stripped wire and "naked" wire (totally stripped wire) to solder to each LED lead. I figure this will make it easier to de-solder the connections when I want to use the LEDs in another project.
 
I soldered the black wire to the inner circle which should be the cathode or short lead on the LEDs. I then was about to wire red wire to the outer ring when I remembered the resistor. I decided to solder the resistor to the red wire on the battery holder and use the other lead to solder to the outer ring.

It was then that the idea of a switch came up. With my parts supplier being closed at the hour this project was being completed, I opted for a loose connection. That way I could remove the connection and turn off the “bucket-o-lantern” whenever I wanted to.

Step 4: Bucket-O-Lantern Complete!

Well, I tested it before installation in the bucket and was pleased with the intensity of the LEDs. I then placed a liberal amount of electrical tape on the back both to insulate the connections and to secure the whole thing to the foam-core. Of course, I left a little part exposed so that I could make the contact with the red wire.

Overall, I was very happy with the project. I was excited that the lights could be seen even with the lights in the room on. I am a relative novice with more "book" learning than hands on experience. It has been very reassuring to me and encouraging to explore these Instructables and get the sense that I can do some of these projects. This was my first real jump into the deep end (Okay, it was relatively shallow).

I was able to field test it at a Trunk-or-Treat and it was a crowd favorite both before and after the sun went down. It fetch quite a lot of candy too, which is why this instructable is a few days late. I had to come down from the sugar high!

I estimate that a child in the 5th or 6th grade, with guidance from an adult could manage this project with no difficulty. The soldering was not tricky and I was able to solder my first project without burning a hole through the foam-core or my hand!
 

Improvements for the Future

 

I originally wanted to use my Arduino and my BlinkM, MaxM but I didn't have time. I would love to add sound too and some interactivity to it. I suspect though a sensor that responds to sound, infra-red sensor, ultrasonic sensor, or light sensor, might need to violate my first rule: I didn't want to ruin the container. 

I welcome any and all comments! Thanks for reading!

Todd
I like it! Maybe I will try this next year

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