Once the heart pieces are printed, it's time to mount and motorize them!
For this step in the process you will need some scrap cardboard, scissors/hobby knife, and a hot glue gun.
Cut out a square of cardboard about 5 inches to a side.
Cut a rectangular hole in this piece of cardboard just large enough to push the servo motor into.
Use hot glue to add an offset disc to the motor hub.
Start small, you can always glue on larger discs to amplify the beating of the heart if the motion is too subtle.
Now is a good time to connect your servo motor to Circuit Playground Express and test out its functionality.
Once the base is ready, it's time to prepare the heart for mounting.
Cut 4 strips of cardboard, each about 1 inch wide and 5 inches long.
These will be attached with hot glue to each of the four heart quadrants, acting like hinges to allow each quadrant to move back and forth independently.
Glue to Base
Adjust the bend in each strip of cardboard, if necessary, so that each piece of the heart lines up nicely with its neighbor.
It's helpful to use a pen to mark the four positions around the servo motor, keeping the placement of each roughly equidistant.
To create the outer layer of the heart, cut the end off one leg of red pantyhose (available here).
The compressive force of the elastic fabric will hold the quadrants of the heart pressed inwards.
The stretch of the hose holds things nicely. Non-stretch fabric may not hold things together as well.