Solar Pumpkin Lights

by drakesword in Circuits > Electronics

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Solar Pumpkin Lights

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Every Halloween countless children and adults carve pumpkins to show their spirit. Usually the pumpkin is lit up with a candle or two. Candles, if watched, are usually safe. But if left unattended the candle could become a burning inferno causing thousands of dollars of damage or even loss of life.

My submission this year is a simple one. Reduce the risk of fire by replacing the candle with LEDs. But why stop there. In this instructable I will also show you how to keep it green as well by using scavenged solar garden lights.

Materials and Tools and a Quick Start

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This Instructable will require:
At least 1 solar garden light per pumpkin being carved
The pumpkins
Some wire
Solder
And possibly some AA sized ni-cd batteries

For tools:
A screwdriver (if the solar garden light can be disassembled)
A knife or boxcuter(have a parents help with this if your a young-en)
A hot glue gun
A soldering iron
Wire Strippers
A rotary tool

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Typically the top of solar lights twist off of the base.

Then the top will come apart in one of two ways(that I have seen so far)

A.) There will be screws with the heads on the underside.
If this is the case then remove the screws then the bottom and the top will separate. Remove the control board by hand (if you can).

B.) The halves are pressed or welded together.
If this is the case then you will need to carefully cut and pry the halves apart.


Once you have the two halves apart you will need to separate the solar cell.

I gently pried the solar cell from the top (it was held in place with some silicone) and cut the three wires.

The lower half, which holds the control board and acts as a battery holder, was then trimmed to a minimal size.

I suggest using a rotary tool to trim the edges of the plastic. This plastic (typically exposed to a good amount of UV) tends to crack and shatter when using snips

Carve the Pumpkin

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First a small note:
Make sure you make the hole in the top of the pumpkin large enough to slide your control board in!

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Get creative and carve your pumpkin.

When your finished take the top and cut a small notch wide enough for 3 wires to pass through

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Note: For more detailed designs I use a dremel rotary tool with a flex shaft!

Modify the Solar Garden Light

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Now that you have a carved pumpkin and a slightly smaller garden light you need to do a couple modifications.

First off if you haven't already, trim off the excess plastic as much as you can. This will make it easier for positioning the light in the end.

Next we need to make the wires longer so the solar cell can remain outside of the pumpkin so the batteries can charge.

1) Roughly position the light inside of the pumpkin.
2) Take some wire and cut it so that it is long enough to go from the control board to the solar cell
3) Strip the wires and proceed to solder them in the color order they are on the cell.
4) Verify that the light illuminates when the cell is covered
5) Tape up the bare ends

WARNING:
Soldering irons get hot and the flux within the solder can pop sending tiny bits of molten solder at your eyes! WEAR SAFETY GLASSES!

Wraping Up

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Place the control board and battery assembly in the pumpkin. For max illumination position the LED so it faces forward.

Replace the top of the pumpkin threading the wires through the notch. Place the solar cell so it faces forward and tack it in place with a drop of hot glue.

Now put the pumpkin on the porch or in a spot where it will get some sun. If everything went ok you will have a safe pumpkin lit up at night only.