Glowing LED Gummy Candy

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About: Making and sharing are my two biggest passions! In total I've published hundreds of tutorials about everything from microcontrollers to knitting. I'm a New York City motorcyclist and unrepentant dog mom. My ...

Let's make glowing gummy candies that look like LEDs! The recipe for gummy candy is simple, the legs are 3D printed, and the special ingredient to make the candies glow under blacklight is vitamin B2 powder.

For this project, you will need:

As an additional experiment, we'll add real surface mount LEDs to the inside of some of the candies.

Warning! Coin cell batteries can cause serious injury if swallowed. Keep coin cell batteries out of reach of small children!

Step 1: Making the Mold

You'll need a food safe mold to make these candies, which you can buy in all kinds of fun shapes like bears and hearts and stars and stuff, but not in the shape I wanted, so I made my own mold.

Flash back to a few years ago when I first made LED gummies as one of my Adafruit projects. I used foamcore, hot glue, and a few packs of 10mm LEDs to construct a mold form.

I had ordered food-safe silicone, which comes in two parts, measured it by weight, and mixed the two parts very very thoroughly before pouring it into the mold form.

My colleague Paige wrote an amazing free online Instructables class on moldmaking and casting if you want to learn more about how to do those things properly.

I followed the instructions that came with my food safe silicone, including baking it at a low temp for several hours followed by hand washing. Before making the candies, put your mold in the freezer to help the candy cool faster during casting.

Step 2: 3D Printing the LED Legs

Before we make the candy, there's one more thing-- the LED candies need LED legs, or they just won't look right. Way back when, Matt Griffin modeled this tiny little toothpick like piece of 3D printed plastic using Tinkercad. So I printed out a fresh batch in silver PLA filament. 16 of them print in 15 minutes (at 100% infill with no raft), so it's easy to churn out a whole bunch. Don't eat these plastic bits.

Step 3: Gummy Candy Recipe

This gummy recipe is based on SFHandyman's Lego brick gummies tutorial.

When I made this project the first time, I made a major oversight in not lighting up the candies themselves, so today I'm here to fix that.

Start with 1/3 cup cold water in a heat-resistant mixing vessel. Stir in 3 capsules worth of B2 powder. Slowly sprinkle in 3 packets of plain gelatin as you stir to keep it free of lumps.

Let the mixture rest on the counter for ten minutes so the water and gelatin can dissolve completely.

While you wait, you can set up a pan of water on the stove to simmer.

After ten minutes, move your mixing vessel into the simmering pan to melt the gelatin down. Don't bother stirring it, you'll only introduce unwanted air into the mix.

Once it's completely melted, add in the packet of jelly dessert mix slowly and stir slowly to reduce added air, which makes the candy cloudy.

Turn off the heat and then add the ascorbic acid and stir to dissolve.

Put the mix in the fridge for about five minutes to get it to cool down and also separate into layers. As the air leaves the mixture, it leaves super clear candy at the bottom and cloudier candy up top.

Step 4: Casting the Candies

The gummy stuff is a bit difficult to clean, so I set up my station with parchment to catch any drips, and my 3D printed LED legs nearby.

After the candy has cooled a little, use the candy syringe to pull up the super clear stuff from the bottom, then squeeze it into each cavity of the mold. There's a sweet spot as the candy cools that will make the placement of the LED legs easy but also with holding power. Don't expect a 100% yield on these... some will be much less perfect than others.

Allow the candies to cool, optionally chilling them down to speed up the process, then flex the mold to take them out.

Step 5: Shine Under Blacklight

Shine a little UV light on the candies to watch them glow!

Step 6: Real LEDs Inside...

To take this concept further, I pulled out my surface mount LEDs and soldered wires onto them, which I then wound around the 3D printed legs before inserting in the candies. Remember don't eat these, they have solder on them. Even if it's lead-free, that stuff is no good.

Thanks for checking out my Instructable! If you like this project, you may be interested in some of my others:

To keep up with what I'm working on, follow me on YouTube, Instagram, Twitter, Pinterest, and Snapchat.

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    15 Discussions

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    misha.bagrianski

    8 months ago

    I like it! What about other components? Do you have plans?

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    photony

    8 months ago

    SURE...and then kids will pop REAL LEDs into their mouths...Did you THINK of that when you were making these? I have to give this a THUMBS DOWN

    3 replies
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    IsaacPiercephotony

    Reply 8 months ago

    LOL, just tell the kids not to put real LEDs in there mouth. I like this idea and there is nothing wrong with it.

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    bekathwiaphotony

    Reply 8 months ago

    I did think of that, but thank you for your feedback. If I never made anything that had the possibility of confusing a child, I'd never make anything at all. If a grownup makes these for a kid in his/her life, I'd expect it to come with some kind of fun comparison study between the real thing and the candy.

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    Eee1997

    8 months ago

    button cell batteries, colorful candies, little kids. Sounds like a recipe for disaster.

    3 replies
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    bekathwiaEee1997

    Reply 8 months ago

    The basic recipe doesn't have any electronics or batteries involved.

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    Eee1997bekathwia

    Reply 8 months ago

    but, you show lighting the leds with button cell battery! Please beware. Kids will put anything in their mouths especially if it looks like candy.

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    bekathwiaEee1997

    Reply 8 months ago

    Thanks for your feedback. At no time does this guide suggest giving coincell batteries or even these candies to small children.

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    KeithD2

    8 months ago

    I am wondering if the smd LEDs could be cast into food grade clear silicone prior to embedding in the gummy LEDs (which might need to be larger), so that the end result would be an edible light up LED (so long as you didn't eat the silicone along with it!)

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    bekathwiaKeithD2

    Reply 8 months ago

    It's possible you could find caulking that fits the bill for this purpose, but I'll let you folks go there if you want to, as I've already angered the safety trolls enough as it is... =D

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    inconceivable1

    8 months ago

    cool! just dont eat the whole thing! XD

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    SimonRob

    8 months ago

    very cool ! it could be a nice project in "science of cooking contest" ;)