Introduction: The Mini Pumpkin LED Face



This is a very simple and fun project for kids as well as adults. Using a small pumpkin as a circuit board I created an LED face powered by a 9v battery. This can be a neat little Halloween decoration for work or home. Now, on to the instructable.

Step 1: Materials


The main materials for this project is a little pumpkin (bought for about 70cents), a couple resistors and 7 LEDs.

5 LEDs were used for the pumpkin face and 2 for the eyes. Two current limiting resistors will double as eyebrows for the face.

Step 2: Circuit Design

The blue and red LEDs are connected in parallel with a resistor to ground as shown in the diagram. Since here we are using one resistor for multiple LEDs in parallel be sure to use one that has the proper power rating.

  • The voltage drop across these blue and red LEDs are 4.5V and 2.2V respectively.
  • The voltage across the resistor with a 9v source and the blue LED in series is 4.5V
  • The voltage across each resistor with a 9v source and the red LED in series is 6.8V
  • The power dissipated by both resistors is ~90mW

Tips

If you are going to try different LED and resistor configurations here are some guidelines.

  • Connecting your resistors in parallel rather than in series is a lot easier since you have to do the soldering inside the pumpkin.
  • If you use blue LEDs you will not be able to hook them in series with a 9v source since there is typically a 4.5v drop across the high intensity type.
  • If you are hooking the LEDs up in parallel like we are here and you use a lower valued resistor (<100ohms) you will probably need one with a higher power rating

Step 3: Cutting Open the Pumpkin


Use a knife cut a hole in the bottom, remove the inside pumpkin seeds with a spoon.
Once most of the seeds are removed you can use a paper towel to clean it out.




Step 4: Adding the Components


Push the the LEDs and resistors into it to the pumpkin to make a face.
Here we use 5 blue LEDs for the mouth and 2 red LEDs for the eyes with the resistors as eyebrows.


Step 5: Wire It Up



Twist and solder the leads of the LEDs togther.
To keep everything in place you can use hot glue or electrical tape.
Attach the 9v and GND connections to the 9v connector.

Step 6: Let It Glow



Connect the battery, turn it over and you have a pumpkin with an LED face

Comments

author
Ploopy made it! (author)2013-11-23

Cool!
I just brought a mini pumpkin and I was wondering what to do with it
and here it is a led pumpkin.

author
dragonx34 made it! (author)2009-09-05

that is cool

author
Radioactive_Legos made it! (author)2008-10-11

That's very cool! I'm surprised that the pumpkin doesn't short out the components. Someone should sell a kit that has a flexible PCB inside the (fake) pumpkin so you can just snap in the LEDs in the position you want for different faces.

author
Shifrin made it! (author)2008-01-03

Wow, awesome!

author
GorillazMiko made it! (author)2007-11-19

Another easier way to figure out what resistors you need, you can go here: http://ledcalc.com/

author
guyfrom7up made it! (author)2007-10-25

nice looking pumpkin there, great idea! Looks like you got all of your tools at the shack. Is your soldering iron the 60 dollar one?

author
jarv34 made it! (author)jarv342007-11-01

the soldering iron i had for awhile and i think it originally came from the shack. leds are expensive if you pick them up at radioshack so i suggest buying online somewhere like ebay.

author
gmoon made it! (author)2007-11-01

Congrats--you've gotten "hack-a-dayed"!

Permalink here...

author
DIY Dave made it! (author)2007-10-26

cool

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