原创 Project idea: DIY practical joke

A member of the EETimes community who prefers to remain anonymous sent me a rather interesting email several days ago. This message was as follows:

Hello Max, I've got a fun project idea. Since I know I will never get around to making this thing, I'm giving you the idea and the rights to the idea, so maybe you'd enjoy making it -- not that you need any more projects!

This is a practical joke idea. You have a:

• 10" x 10" x 10" wooden box
• With four short rubber feet
• With a power cord going to a wall outlet
• And with a toggle switch with the two positions labeled "Off" and "On"
• The switch is in the "Off" position
• The box is sitting on an end table
• Next to the table is a chair where a bored person might be sitting (think "lobby")

Here's the scenario:

• The bored person can't help but wonders what the box is for
• Curiosity gets the better of him (or her) and he flips the switch to "On"
• The box immediately starts emitting a moderate, yet annoying, tone that is a little too loud and disruptive for an office environment
• The startled person immediately flips the switch back to its "Off" position
• But to his or her surprise, the tone doesn't stop
• In fact, it goes up in pitch, up in volume, and starts beeping
• Further attempts to cycle the switch only make noise that is higher in pitch, louder, and with faster beeps
• Nearby people pop up like prairie dogs out of their cubicles to see what is causing the disruption
• Not wanting to disrupt the office, the person leaps to his or her feet and unplugs the device from the wall
• But, to his or her surprise, the beeping doesn't stop
• In fact, it goes further up in pitch, further up in volume, and the beeping grows faster and more frantic
• The person turns the box around and over, but cannot find any other controls
• By now this person is really panicking
• At this point, the nearby prankster steps out and silences the box, plugs it back in the wall, and resets it for the next victim

And here's what the victim didn't know:

• The on/off switch is not an on/off switch
• The switch connects to GPIOs on a microcontroller, to detect switch position
• The power cord does not power the box
• It charges the large-ish battery inside the box, which provides the real power to the always-on microcontroller
• And the powerful audio amplifier, which is connected to a strong speaker camouflaged into the base
• The rubber feet space the base of the box up from the table, allowing the loud sounds to escape
• One of the rubber feet is actually a rotary switch to cut the power
• Another rubber foot is a rotary reset switch to the microcontroller
• Which also synthesizes the audio tones, and sends them to the amp

Fun, huh? If you ever get out to my neck of the woods, the beers are on me.

Well, he certainly closed on a good note (LOL). I must admit I'm tempted to build something like this. We have a sort of sitting area just outside my office that would be perfect for this sort of thing, but it will have to wait until I finish up some of my current projects.

Actually, this reminds me of those "Do not push this button" videos. You know the type of thing, like this one or this one.

What can I say? I'm a weak man. I really would like to have something like this lying around to break up the monotony of our visitors' days. Deploying it would almost be a public service when you come to think about it. What do you think? Would you modify the system discussed above in any way, or would you implement it as described?