Have you ever used your clapper to turn out the lights at night — and then drifted asleep, dreaming of something even bigger? Like, what else could you possibly clap-on, clap-off? Well, one person dared to dream that dream — and they're here to show you how to apply the same technology to make your own clap-off over the shoulder bounder holder. (Actually, I'm pretty sure this thing won't hold boulders — maybe small gem stones?)

Laughing Squid points us to this how to for a clap-off bra. It looks like waaaay more trouble than it's worth — I actually haven't figured out its worth, except maybe in a burlesque performance? Or perhaps you have an affinity for mechanical underwear? — but if you want to get started, you'll need these things:

A front opening strapless under-wire bra
Black fabric
Small nut and bolt
(x2) Prototype circuit boards
An Arduino (w/ATMEGA168 DIP chip)
28 pin socket
(x2) 22pF capacitors
(x2) 0.1uF capacitors
10uF Capacitor
16mhz crystal
1K resistor
10K resistor
100K resistor
2N3904 NPN transistor
7805 voltage regulator
5V SPST relay
5V DPDT relay
An electret microphone
9V battery connector
A spare USB cable
1" shrink tube
Threadlocker
A small grommet
Elastic band
Double stick tape
Quick-setting epoxy
Ribbons and frills
Sewing stuff
Soldering stuff
Tools of various sorts

Sounds like it's totally worth it for a novelty brassiere. Good luck!

[Instructables]