Lit Valentines Card

6 days left until Valentines day. This last year has been a tough go, with both my wife and I teaching online all year. She's an amazing lady, and has handled 2020 (and a grumpy spouse who misses in-person teaching) like a champ. I wanted to make her a special Valentines card that is "Extra" just like she is. So the card is Lit! Don't tell her yet, she doesn't know about it.

This is a super simple build, and you need no electronics experience or soldering skills. It is all scissors and glue and tape and paint.

Cardstock

LEDS (surface mount 3014 is what I'm using)

Aluminum foil

CR2032 Cell

Automotive defroster repair paint

Superglue

Woodglue

Fold your foil. Then draw a heart on that, but make sure it has a couple of inches of "Tail" coming off the point. You will use this as a contact later.

Glue the heart to your cardstock, a bit below half-way up the sheet. I use Gel type Gorilla glue as it bonds well.

Do not glue down the tail. Make sure it is free of the paper.

Take the foil you cut the heart out of. Use your scissors and trim off a sliver (about 4mm) from the foil.

Test fit this piece around the heart. The central heart and outside outline cannot touch at any point.

If it looks good, super-glue it down, a half at a time. Make sure the bottom tails are also free.

I had a few SMT LEDS leftover from a previous project. So I decided to use these. https://www.lumileds.com/wp-content/uploads/files/...

These were all 3014 style, meaning they were 3mm long by 1.4mm wide. Tiny little things, so you need to look at them carefully as they need to be placed properly. The yellow side is the Front (light), and the backside with the metal tabs is what we will need to connect to. Identify the end that has the longest metal tab as the Cathode (this is the negative side).

I put down 6 dabs of superglue and used tweezers to put these front-down. All the cathodes were faced out from the central heart. This is very important, as otherwise they won't match the battery polarity and therefore won't work.

I used the leftovers from an automotive window defrosting repair kit to make my connections. This is a special type of electrically conductive paint used to repair damage on rear-window defroster. And although it is conductive, it is also resistive enough that no external resistors need to be used with the LEDS and battery.

Each LED gets "Painted Down" to make contact with the metal at either end. Make sure that there is always a gap in the paint and that the paint from the central heart is not touching the paint from the external outline. You can see it in all the pictures, and really well in the one close-up. If the paint would cross, that would short the system.

I used a lithium coin cell for power. These are 3V rated.

Each of these batteries has a Positive side (+, or "Big" side) and negative (- or "small" side). The negative needs to go to the outline foil, and the positive to the inner heart foil.

If I would just tape the battery in, the cell will constantly run and then rapidly deplete. So I made a simple Pressure switch.

• Cut a ring out of cardstock slightly larger than the battery.
• Trim a smaller ring out of that.
• Superglue the cardstock onto the outline foil
• Tape the battery + to the heart+tail, then tape the whole battery over the ring with the negative down.
• Make sure the heart+tail are not in contact with the outline. There is a little bit of tape isolating them on mine.

Now test this all by pinching the battery against the ring. When you do, the lights should illuminate. If not, make sure the outline and heart have no shorted components. Reverse the battery and test as well in case you connected your LEDS opposite.

You should see a little pattern of lights through the cardstock when you pinch the pressure ring. If not, check each the previous step.

Fold your cardstock in half. Then use glue to close it all. I am using carpenters glue.

The cardstock might warp as it soaks in the glue, but keep it with the good side(LED side) down so that stays flat.

Mark a little "x" with pencil on each lit spot, then draw in your heart. I put a stick figure over the pressure switch, then and trimmed down the sides a little bit as well.

Decorate the rest as you wish. I'll be writing something more on the back, but that's not for you all to see!

If you like this, please vote in the Tinfoil contest and maybe I can give my wife an Amazon card as well!