Introduction: Tiny LED Jack-O'-Lantern

By www.zackscott.net

Ready to spice up your craft-making skills this Halloween season? Say good-bye to your candles! Here's how to make a small, high-tech, jack-o'-lantern that uses a bright LED.

I was actually inspired by this project:
Evil Mad Scientist Laboratories

I liked the idea, but I really wanted to design my own circuit that I could switch on an off, and I wanted to use a different LED color and pumpkin size.

Step 1: Pumpkin Carving Materials

For this project, you'll need a small pumpkin and some carving tools. This pumpkin was sold at my local store as a pie pumpkin, but it's perfect for carving. Plus, it was less than $2. I also used a $1 pumpkin carving saw and a spoon for all of the actual carving, but just use whatever you'd like

Step 2: Carve the Pumpkin

First, carve out the top of the pumpkin like normal, and remove the innards. Then, carve a face or other design into the pumpkin. If you're not very good at carving faces, I suggest having your spouse lightly draw a face on the pumpkin with a pencil. That's what my wife did!

Once you're done, you'll have a tiny jack-o'-lantern that looks great by itself. But don't eat it, because we're going to kick it up a notch!

Step 3: LED Module Materials

Let's build an LED module to light your pumpkin. For this, I'm going to use the following:

  • One (1) ultra-bright red LED (2.4 V, 20 mA)**
  • One (1) 33-ohm resistor
  • One (1) SPST switch***
  • Two (2) AA batteries
  • One (1) snap connector (typically used for 9V batteries)
  • A four AA battery holder

** This particular red LED provides 5000 mcd of luminous intensity, which is enough for small pumpkins.

*** You'll notice that later in the video I am actually using a DPDT switch. I had a lot of those, but I only had a few SPSTs.

Step 4: Circuit Diagram

For those of you who are interested, this is the circuit I designed. It is very simple. Basically, I am providing 3V by using the two AA batteries. The LED is rated at 2.4V and 20mA, so in order to provide the proper current, this is the calculation I did:

  • V/I = R
  • (3.0 - 2.4) / (0.020) = R
  • 30 = R

The closest resistor I had was a 33 ohms, so that's what I used.

Step 5: Connect the Resistor

First, connect the resistor between the two terminals in one of the top battery slots. For a more secure and durable connection, you can solder it in place.

Step 6: Connect the LED

Next, connect the LED in the adjacent slot in the same manner. Feel free to solder it in place if you need to. I decided not to so I can easily switch out LEDs whenever I want.

Step 7: Insert Batteries

Next, insert the two AA batteries into the bottom slots.

Step 8: Attach Snap Connector

Then attach the snap connector to the side terminals. Make sure the LED remains connected as well.

Step 9: Test Module

Be sure to test your LED module by briefly touching the two leads at the end of snap connector. The LED should light up.

Step 10: LED Module Complete!

Now your LED module is complete. Your module doesn't have to be this big though. It won't look bad in your pumpkin, but it will be noticeable. I chose to use these parts because they minimize the need for soldering and they make it easy to switch out LEDs and perform testing. Plus, I had them in my tool box. But, if you're good at wiring and soldering, don't use the battery holder. Also, try using AAAs to further minimize the size.

Step 11: Carve Switch Hole

It's back to carving! Cut a small slot in the back of the pumpkin to hold the switch. Make sure it isn't too big or too small.

Step 12: Insert the LED Module

Next, insert the LED module into the pumpkin and make sure to pull the two wires out through the back slot.

Step 13: Wire the Switch

Carefully connect the wires to the switch, and solder them in place if you'd like.

(Note: This is when I started using a DPDT switch instead of the SPST switch I recommended earlier.)

Step 14: Mount the Switch

Finally, mount the switch. Feel free to use screws, hot glue, or some other adhesive to make sure the switch stays.

Step 15: Jack-O'-Lantern Complete!

Awesome, the mini LED jack-o'-lantern is complete! You'll find that the switch comes in handy. Here are a few photos of it in various lighting. It really looks great in darker areas, especially for its size. Compared to a candle, the steady, ominous red is pretty cool. But if you don't like the color and brightness, and you know what you're doing, simply adjust the number and type of LEDs to your liking.

This tiny, electronic, jack-o-lantern that will outlast any candle. And since you don't have to worry about fires, this is perfect for the home or the office. Thanks for reading, learning, and watching. Have a fun and safe Halloween!