Romantic LED Heart




Introduction: Romantic LED Heart

About: Born in Naples, Italy, lover of everything concerning about technology. Currently studying Automation Engineer at Federico II University of Naples.

Hello Instructables! This is my entry for Make It Glow Contest.
Who said that electronics can’t be romantic? We can use it to show a person our love, and it is exactly what we are going to do: a present, as simple to realize as wonderful to see, to give to the person we love.
It could be a great gift for Valentine’s Day or anniversary.

The idea is to realize a casket which has inside some little red LEDs arranged in a heart shape.
A switch turn the LED on and off.

You can see the final result in the picture above. It's amazing!

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Step 1: What We Need

These are the components we need:
  • a casket (mine is priced ~€2.50);
  • 27 red LED (~€6.00);
  • one 220Ω resistor;
  • one switch;
  • one battery case (4 AA batteries);
  • black cardboard (better if rigid);
  • soldering station
  • optional: a third hand (~€6.00) is really useful during soldering.

Step 2: Making the Heart

Cut a piece of cardboard of the same height of the casket, but with a greater length: on one side, a flap will be sticked inside the casket, while, on the other, the cardboard encloses the battery case. My casket’s size is 12 x 6.5 cm, so the cardboard is ~16 x 6.5 cm.

Now, the heart. Using a 2D vector graphics software (I recommend Inkscape), draw a heart, formed by 27 circles, diameter ~0.6 cm. I provided the one I made, but feel free to modify it as you want.
Print it, place it on the cardboard, and make holes in correspondence to the circles: there you will place LEDs.
I used a belt puncher.

Step 3: Soldering

The third phase begins: soldering.
Insert LEDs in the cardboard through the holes and connect them in parallel, which means every positive leg with positives and every negative with negatives.
I recommend to use a third hand and insulating tape.

Pay attention: do not connect a positive leg with a negative one, or the circuit won't work!

Connect one positive leg to the 220Ω resistance, and then to the switch (make another hole in the cardboard for it).
Finally, close the circuit connecting the battery case.

Step 4: Conclusion

Enclose the battery pack within the cardboard. On the opposite side, fold a little flap and stick it inside the casket.
You are ready to show your love: turn it on!
I assure it's as beautiful to look at, as simple to make.

(Sorry for image's bad quality)

If you like this instructable, please vote me.
Thank you!

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10 Discussions


3 years ago

Brilliant work. How many watts(W) in the resistor?


5 years ago

could you take a picture of the other side of the leds? because I cant think of how you did it, unfortunately. thank you!


Reply 5 years ago on Introduction

I'm sorry but I gave it out as a gift, so I cannot take photos now.. but I could try to explain you.

Hole the cardboard and insert LEDs. Now, bend LED's pins so that every led touch the next one. For example, take the LED on the upper-left corner, and bend its pins so that they touch the next LED, and solder them. Then, do the same for every LED: you'll eventually have every LED connected with the next one (positive to positive and negative to negative), and the last LED connected to the resistor.

I hope I've been clear enough.. if you need help, just let me know :)


6 years ago on Introduction

Thanks for this idea. My wife and myself agreed to not get each other stuff for Christmas (we can get more stuff for the kids that way) but I think that I'll be making this for her. I might put some type of cloudy type of paper or plexi-glass over the LEDs to make it look even nicer.


Reply 6 years ago on Introduction

I am very very pleased to be a source of inspiration. I am sure she will love it, because it is a very nice thing and is made with passion.
Thank you :)


6 years ago

I'd say its a nice gift to give away :-) ..
And if you want ideas on how to make the lights go on automatically ->


6 years ago

first I think it is a really nice idea but I have some remarks 1. I believe you can pull off the same with a 2AA batteryholder or set in every parallel part 2 in series. In that way it is more power efficient. and while AA battery is 1.2-1.5 volts and most red leds are 2-2.3 V off course a other resistor value should be chosen. 2. It would be nice to use a switch that switches on when you open the box. ie. with magnetic switch or be creative with creating you own small circuit. 3. I can't see the vote button ;)


Reply 6 years ago on Introduction

Hi marcoboers, thanks for your comment! It's always a pleasure the read constructive comments.
First: yes, I think it would be a better solution. I have to say that, when I did it, I was forced to finish it in less than a day, and the 4AA battery holder was the only one I had. Moreover, I have no much experience.. I can only improve, so, your comment is really really appreciated.
Second: Surely, it is a nice idea that should be followed!
Third: I am waiting to be accepted in the contest, and it takes one or two days.
Thank you!!