Valentine STEM: Light-Up Circuit Valentines (2024)

Did you know that you can paint on an electrical circuit? Neither did I until I stumbled across some electric paint a few months ago. And it’s as easy to use as glitter glue. Really. Ever since I found it, I’ve been dreaming up projects… Valentine stem projects like these Light-Up Circuit Valentines. They’re conversation hearts with their very own LED & battery, made just for the light of your life. For Valentine’s Day or any other day, you want to show your love. This post contains affiliate links.

How to Make Light Up Valentine Circuits

Definitely don’t be intimidated by these Valentines! Kids all over the world have made these in class, at home, after school, in scouts, at libraries, and more. All you need are a few supplies and this helpful printable template. To grab the template, just fill out the form and it will be emailed to you.

Coin Cell Battery Safety

Coin cell batteries pose a serious risk when swallowed and should not be used or stored within reach of small children. This project is intended to be performed under adult supervision. Appropriate and reasonable caution is recommended when activities call for any items that could be of risk, including, but not limited to: sharp tools, hot glue, chemicals, batteries, scissors, and small items that could present a choking hazard. If you are unsure of the safety or age appropriateness of an activity, please consult your child’s doctor.

Copper Tape Light Up Valentine Circuits Update

I’ve heard from a lot of you that it’s hard to get the pin batteries these days. So I’ve updated the template so you can use copper tape and standard CR2032 batteries.

Copper Tape Light-Up Circuit Valentines Supplies Needed

Here’s what you need to buy (be sure to grab the free printable, too by filling out the form at the top of this post):

• Card stock
• 1/4″ Copper Tape
• CR 2032 Coin Cell Batteries
• 5MM LED Bulbs
• Paper or Binder Clips (optional)

How to Make Copper Tape Light Up Valentine Circuit Card

1. Have the template emailed to you by filing out the form on this page. Print out the template and then cut along the outer pink heart line.
2. Build the circuit:
   • Bend the leads on the LED at a 90-degree angle so that they can lay flat against the cardstock. If the leads are too long to follow the heart line, you can cut them shorter, but make sure to keep the positive lead longer for easier building.
   • Now for the copper tape… Always try to use long continuous sections of copper tape without breaks. If it does break, give about an inch of tape overlap with the next section.
   • Tape the positive LED lead with copper tape so that it secures the lead to the card and travels down the right side of the heart, all the way to the switch tab battery section.
   • Repeat with the negative LED lead and tape down the left side of the heart to the positive battery circle.
   • Place the battery with the positive side up and close the card. You can secure the battery to the card with a loop of copper tape or a piece of clear tape. To turn on the card, close the switch with your finger or paper/binder clip.

And back to the original post….

DIY Light-Up Valentines

OK, I’m going to be honest here. This is one of my absolute favorite projects that we’ve done at Left Brain Craft Brain. I always joke that if something is shiny, I want it. If it lights up, even better. My daughter gathers light-up toys and glow sticks at an alarming rate simply because I love them too. So when I had the chance to do a Valentine’s stem project that lights up, I was all over it.

It’s often hard to find simple technology projects to round out STEM / STEAM learning, but this Valentine stem project is truly easy enough for a kiddo to do. My preschooler needed a lot of hand-holding, but an early elementary-aged child could do this all by themselves.

Light-Up Valentines Supplies Needed

• Bare Conductive Electric Paint Pen {affiliate}
• 5 mm LED lights {affiliate}
• Pin contact coin cell batteries, 3V 120mAh {affiliate}
• 8 1/2″ x 11″ pastel card stock or scrapbook paper {affiliate}
• Push pin

1. Print and cut the Valentines: Print out the free Light Up Valentine Circuits Printable. Cut out hearts along the black outer heart-shaped line, making sure to cut out the square part on the lower right as well. This will be the switch for the Valentine.

2. Insert the LED:First poke two holes in the card with a push pin, one at each black dot near the circle with an x in it. This is the symbol for the light. Then insert the LED, making sure that the long pin is inserted into the hole with the + sign. Fold the wires flat on the back of the card.
3. Add the battery and paint the heart circuit: Place the battery as shown on the Valentine with the positive pin aligned with the plus sign. Please note, coin cell batteries are hazardous if swallowed so be sure to keep these away from kiddos that still put things in their mouth.
4. Start painting the electric paint along the pink inner heart line. You don’t need a super heavy line (this isn’t puffy paint), but be sure you get a continuous line of the paint that’s about as wide as the pink line. If the line is too thin, the LEDs don’t get enough power. Do not fill in the area where the battery or LED go, or the blank spot by the switch.

5. Paint the switch: Fill in the pink square with electric paint. Use just enough to cover the square with a light layer. It’s really easy to use too much here which makes it take forever to dry.
6. Let it dry: Let theconductive paint dry. The paint instructions said 15 minutes, but I must have applied a heavier layer so it took a few hours. The paint becomes fully conductive only when it’s completely dry.

6. Light it up: To turn on the Valentine, fold the switch over so that it completes the circuit. The LED will glow.

You know why else I love this project? My daughter definitely lights up my life :)

More Hands-on Valentine STEM Projects for Kids

If you love this, you’ll love these, too!

25+ Valentine Process Art Projects for Kids

Valentine's Day Science, Tech, Engineering, Art, and Math Fun for Kids

Looking for ways to show your love for STEAM? Instant gratification style? Check out STEAM Kids Valentine's Day! It’s packed with 14 heart-inspired activities that will wow the boredom right out of your kids.

UPDATE: A few people have asked me about where to get the batteries. I’ve linked above to Amazon because it’s the easiest way to get all of the supplies together

. You can see a list of all of our circuit card recommendations HERE.