Some time ago I read that you can use a ping pong ball to soften the harsh light of an LED, so I thought I’d try it out.
Step 1: make a hole in the ping pong ball to hold your LED. For a 5mm LED, an ice pick heated on a stove top is an handy tool for making that hole. I haven’t tried a drill press, but that seems another possibility.
Step 2: set up a circuit to blink an LED, perhaps using an Arduino Pro Mini.
Step 3: press the ping pong ball onto the LED. For a more permanent mechanical connection, you could glue the LED into the ping pong ball using a hot glue gun.
Step 4: Enjoy the magical, diffuse light of the LED in the ping pong ball. You may need to turn out the lights to see it well. Have a look at my low-key YouTube video of the result.
So a ping pong ball really is a quick and easy light diffuser for your LEDs – disco time! …or you can paint pupils on them to create blinking night-creature eyes as in this video.