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).

BE CAREFUL NOT TO GLUE YOUR FINGERS OR EYELIDS! USE AT YOUR OWN RISK!

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.