Valentines Gift With Nifty LED Effect




This HowTo will give you an idea for a present for your girlfriend (or whoever) since, surprise, valentinsday is coming closer!

The result is a little self-made object that shows the initials of two people in a heart. It kind of looks like a hologramm so its really modern.
Since im tinkering around with FTIR and multitouch sensors, building something like this for my girlfriend was not avoidable.

Ursi i luf u! <3

Step 1: Used Parts

What i used in this project:

- plexiglas
- soldering iron
- batteries
- a switch/button
- a led or some other nifty electronical part
- little spring (see picture below)
- jigsaw
- sandskpaper
- instant glue
- scalpel or pointy knife
- time: less then 2h

Step 2: Layout/Dimensions

First thing of course is to measure everything out and to plan what we will build.

My layout looks something like this:

|-----------------------|             |         -->button		|   LED       |  Batts ||             |        ||         --wire-->    ||-----------------------

Step 3: Cutting the Plexiglas

Since we need a box for the present to be presented in, i decided to use 5mm thick plexiglas to build one. I got it from my local constuction supplies store, little parts can also be retrieved from glas factories (they seperate a lot of stuff out because its too little for them, but thats just right for us).

Measurements and dimensions vary, depending on how you want to box your electronics, my final board is about 7x3cm.

When cutting, its better to leave the securityfoil on the plexiglas and to use a high rotation of the blade whilst going slowly with cutting. This way the plastic wont sliver and you have plenty of opportunities to correct your cuttingpath.

Cutting the heart is the hardest. Drawing on the foil helps a lot, but im even bad at drawing hearts. Sanding the borders after i did a miserable job helped a lot. Dont use too fine of a sandpaper (I used P60).

Use the scapel or a pointy and sharp screwdriver to engrave the initials. It took me quite a while since i didnt want to have to cut the heart again. The deeper you scratch, the more light will be reflected in those scratches. You could also fill them with glue or some paint. Open for experiment.

And do remember to keep enough room for the wires to the battery and/or LED!

Step 4: Gluing the Plexiglas

Now that you have all your parts seperate its time to put them together.

For the housing i used instant glue (which works really well on plexiglass and friends).


There are many types of different techniques how a glue works, so read its instructions carefully in order to enable a clean an stable result.

My glew has two components, one to prepare the plastic and one to actually glew parts together. After pressing the parts together for about 10 seconds, they stay at their place. Really dried through probably after a little longer while.

Step 5: Putting Parts Together

Now its time to actually put all the parts into their new home.

Since we measured exactly, that should not be a problem.

In order to provide some power i had to build my own batteryslot.

My device needs about 4.5V so i put 3 times 1.5V AG4 LR625 377 batteries in series. In order to fix them to stay where they should, i installed a little spring which pushes them together. Soldering the specific wires to their contacts and installing the button is not a big deal.

After wiring everything up, i tested it, and then put the lid (which will hold the heart) on top. Glue again.

Step 6: Installation of the Heart - Results

In total, i 'just' glued it to the lid of the box.

Some experiences i made were:
- flat surface with little contact (heart is pointy on bottom) doesnt hold
- drilling a little into the lid helps
- sanding the bottom of the heart to fit into the hole helps alot
-using a lot of glue is the only truth.

After you installed your heart, let everything dry out totally (or tell your girlfriend/friend to let the present dry out totally).

Additionally you could use hotglue to make the seems and borders feel smooth. Will probably increase stability. Just an idea.

Thats what my present looks like, please dont tell my girlfriend yet tho ;)

Hope you enjoyed this instructable and hope your partner will respect the effort (and in my case not the result).

Please feel free to comment and/or give feedback via email.

EDIT: first response is from this guy who used a dremel instead of my bizarre techniques. the result obviously is a big improvement. Nice! (and thanks for the response)

EDIT2: looks like this guy here took some inspiration from this project and did an awesome job on an acrylic heart. Unfortunately i dont know more about its developement, but it looks professional.



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    16 Discussions


    7 years ago on Introduction

    hi can you send me the pcb layout and schematic diagram of it..tnx


    11 years ago on Introduction

    Some time ago I've done very similar lamp for my girlfriend :]. This lamp, called the "angel lamp" for a known reason :], is powered by a 9VDC adapter and inside the wooden chassis there is an electronic circuit which slowly lighten the lamp for a few minutes when the darkness comes. After few minutes the lamp slowly stop lighting. More infos (including circuit) on my website - in polish language only.

    3 replies

    Reply 10 years ago on Introduction

    hey there, sorry i dont have a webpage, sometimes i blog at but thats about it. greets


    Ditto here, where did the circuit board come from? It didn't show on the contents list? How do we go about with it, so the LEDS can fade colors?


    Reply 10 years ago on Introduction

    sry folks, i get that question alot and forgot to mention in the instructable. its taken out of another gadget which is for bathtubs, so the electronics were ready to use. if you look around, you find many blinking lights in cheap toys or other devices that you could easily rip out and re-use. with the right amount of time you could also drive a rgb-led with a microcontroller (and implement other features like remote controll, different light-modes, timer, soundrecognition, etc.). sorry for my late response, ive been very busy lately. thanks for beeing intrested tho. keep us posted about how your projects go. take care


    11 years ago on Introduction

    Heres what i made, used a soap dish as the base, and plexi glass cover. sorry for the blurry pic


    11 years ago on Introduction

    great idea and good instructable. if i make one though the base box will be coated in something opaque. the led glare kind of out shines the heart glow and nothing should outshine love. also most people don't dig the circuitboard look.

    1 reply

    Reply 11 years ago on Introduction

    Hey there,

    yah, since it was pure pre-alpha need to build with what i have, there can be lots of improvements. on youtube, someone built something very similiar but with a closed box with just a little hole for the light. he sent me some building pictures, to bad i have them on my other computer, but check out his video

    compared to my device, the light is much more centered, and his deeper engravement (dremel!) is stronger visible!


    12 years ago

    I do computer modding and I've done a big of cutting of plexi (and times) I would suggest imbedding the leds in groups of the three primary colors along the edge of the sheet. easiest thing to do would be to use a router to make a channel along the edge of the sheet, then drill holes to insert the leds into. You could then use clear epoxy to seal the edge, then sand it smooth, use a plastic chanel molding to put over it, or even a clear rubber hose slit along one side and hot glued into place. On the other hand, flame polishing can make the cut edges shiny again. yeah, I think i've used up my quota for the day... Wet sanding plexi with 1000-2000 grit will leave it with a nice cloudy finish (perfect for the project box so you can hide the nastiness of raw electronics. You could even do it with the initials or

    1 reply

    Reply 12 years ago

    yeah those hints sound like you know your stuff! thank you very much, hope others can apply those to improve their result. i just didnt have the knowledge or time or tools. embedding the leds IN the acrylic is not that easy in my case since im using only one rgb-led which is attached to its driverboard. furthermore i wanted to keep the acrylic heart as electronic-free as possible (you know, girls, blackbox, ...). embedding the leds into the heart would have of course caused a more complete total internal reflection (but since its only for optical reasons and not for multitouch or so i didnt care)


    12 years ago

    this is so cool...if i had the time i would totaly do this right now!!!