I wanted to show my appreciation for the patience my girlfriend has with me when I'm hooked on a new project, so I decided to dedicate a project to her. Well she also pushed me a little bit by buying a small plastic heart and telling me to create something for her for a change :).

So in this instructable I want to show you how to create a beating heart for your loved one.

Step 1: Part List

You will need the following parts:

transparent and hollow heart shaped object
2 x red LEDs
2 x 100kΩ resistors
2 x 470Ω resistors
2 x 100μF capacitors
2 x NPN transistors (BC547)
9V Battery with connector
transparent layer as a circuit board

Step 2: Assemble the Circuit

You want to use a thin transparent circuit board. I took a transparent plastic sheet cut out of a grocery box. You can take anything you like but you may want to make sure that is transparent to let the whole heart glow in the front and in the back. After cutting it to the heart shape of the container object the fun part begins. Make the required holes for the components in your circuit board and assemble the cicuit like shown in the circuit or fritzing schematics.

Step 3: Final Touch

If you use a plastic layer like I did, be very careful to not melt it with your soldering iron. Due to the limited space on the circuit board, you might have to assemble the circuit on both sides to place the capacitors on opposing sides.

If you already used diffused LEDs, you still might only see two dots blinking in the dark. To diffuse the light even more, you can fill your heart shaped container with a thin layer of soft tissue. The heart container I had wasn't big enough to hold my 9V battery block so I cut a small hole at the top to let out the connector wires.

As a last step I attached the 9V battery block at the back of the heart with some tape and connected it to the heart. When everything is finished it looks like this: