My girlfriend is a muggle who love with Harry Potter and fancy everything in the magic world. I made this ring box and proposed marriage to her for surprise.
Step 1: Materials
1. A flapping bird deceleration group from the powerful TaoBao！
2. A pair of 3D printed wings. Thanks a lot to @Porda and his share. I rebuild the wing to a proper size (length＝7.5 mm).
3. A ping pong (diameter≥ 40 mm). It's failed to me to build the core in 3D file because I am a green hand about it. So, I made one by a ping pong.
4. Two 1.5v AG13/LR44 batteries.
5. An electric switch
6. A key ring.
7. A piece of foam plastic (polystyrene, 40x40x20mm)
8. Tools: electric scissors, common scissors, foam plastic glue, tape, heat shrink tubes (inside diameter＝ 1 mm), wires, cotton thread (better in black), golden color marker ( or spray painting).
9. Never forget the marriage ring!
Step 2: Core
A flapping bird deceleration group usually has four connecting bar. Two of them will be used later.
Cut the foam plastic in a proper shape inside the ping pong and dig several holes containing the deceleration group, the switch and the batteries. That's good in balance of my arrangement (see in videos).
Make sure the machine works well and fix the components together by tape and glue.
Step 3: Shell
It's a difficult work to cut a pingpong in the ideal shape. So, prepare more pingpongs or design and 3D print it.
There are 3 hole in the ball: one for switch and thread, one for the wings, one for ring and plug.
The marriage ring and deceleration group are heavy parts. It's sorry that this Golden Snitch couldn't fly by itself. You should hold the thread to raise it up. Gravity translates through the thread to the key ring held in your hand.
Step 4: Print and Assembly
I only have a golden color marker as I used. It will be in better effect if you spray paint it.
Be careful when you use the glue. It's sticky to foam plastic, ping pong and your hands!
The wing root should be polished to diameter as 1 mm in order to insect into the connecting bar. Heat shrink tubes would help to make them tightly so as not to flight accident.
Step 5: Fly and Surprise
Have fun and good luck!