A guide to creating illuminated shapes with balloons and LEDs. Although this instructable demonstrates how to create a red-illuminated balloon heart, these techniques can be used to create most any shape (possibly 3-dimensional) of your own design. The actual assembly of this example took approximately 2 hours to complete.

Step 1: Materials

The materials needed for this project include:

-20 latex balloons
-20 LEDs
-20 3v coin cell batteries
-Sticky-notes
-Tape

I used red LEDs and pink balloons, but any colours will do.

Step 2: Assembling the LEDs

The balloons are illuminated by LED-throwies which are documented in several variations on instrutables. Here is how I made my Led throwies.

First trim down the anode ( + long lead) and cathode ( - short lead) so that the length of either lead is shorter than the diameter of the battery.

After the leads have been trimmed down, wrap a strip of paper around the cathode lead of the LED.
Then, insert the battery between the leads of the LED with the strip of paper. I used scotch tape to hold everything together, but most any tape will do.

Step 3: Assembling the Balloons

I did not have a tank of helium to fill the balloons myself, so I went to a local grocery store and ordered 20 pink latex balloons. I asked if they would mind putting throwies into the balloons before inflating and they were willing to help. So, I left them with the 20 pre-assembled throwies in a bag labeled with instructions to pull the pink slip of paper out to illuminate the LEDs. An hour later I pick up my balloons and was ready for assembly.

I doubled over strips of tape t stick the balloons together side by side. The reason I had popped a balloon was that I pulled the tape on the balloon and the latex ripped. As a precaution I also tied the balloon strings together as a stress relief for the taped areas.

Step 4: The Layout

I had planned on using 20 balloons to complete the shape (see first diagram), unfortunately while taping the pairs together I popped one balloon. So, I reconfigured the layout to use 19 balloons, which worked out well.

Step 5: Final Steps

After taping the balloons into pairs, I assembled the row lengths then connected each row. Here are a few pictures I took of the row assembly.

Once completed I walked these balloons across town to deliver them and not only wowed many people along the way, but also impressed my girlfriend.