Years ago I was working for a small company as a technician. We built custom control systems. Our assembly lab and the lunch room were separated by a set of dividers. Often people would come in for a cup of coffee and stop by to see what was going on in the lab.
Our sales manager, Tom (naturally a talkative kind of guy), would stop by and would always critique what we were building.
He would act as though he was the guy buying and operating the system and start pushing buttons as he was talking.
One day I got a hold of a Klaxon horn and knew exactly what to do with it. I wired it to the start/stop latching relay circuit and waited for Tom to stop by.
Sure enough he came in for a cup of coffee, then proceeded to the lab area.
With coffee in hand he started talking and eventually worked his way around to the front of the control box I was working on.
The first thing he hit was the start button and almost ended up wearing that cup of coffee. He was shaking so badly that he had to set down the coffee so he would spill it.
He did however, have enough sense to hit the stop button to turn it off.
We all had a good laugh, but Tom didn’t come around as often after that. And when he did, he didn’t press any buttons.
Good memory, Stargzer! Would have been about 1964 or 1965. There were 2 neon relaxation oscillators, one was audio frequency and was modulated by the other at about 1 Hz to produce a siren effect.
I was a young teen at the time too, and learned a lot from building this toy.
Back in the mid 1970's, I was the Data Operations Manager for a large multi-national trading firm.
Our programmer, the CEO's nephew, was top notch before lunch. During lunch he would consume 6 Rob-Roys. His after-lunch performance consisted of sitting at the console in a stupor that resembled an automaton, occasionally punching buttons or hitting a few keys until 5 pm.
So, one evening, I took my cassette recorder, a Lafayette bench sine/square audio generator and proceeded to make a recording.
The next day, during lunch, I placed the recorder under the console desk and ran the remote control wire to another desk where I sat and waited for my victim's return.
He took off his hat and coat, walked very stifly to the console and sat down. As soon as he pressed the first button, I turned on the recorder... and there erupted a cacaphony of
electronic noises and a mimic'd computer voice yelling: "THAT DOES NOT COMPUTE! ERROR...ERROR...ERROR!" over and over again. Everyone else in the department was in on the
joke, so they all proceeded about their normal routines during this incident.
Looking around and seeing that no-one else appeared to be aware of what he was experiencing, the man got up from his chair, calmly and purposefully walked to the hat-rack, put on his hat and coat and quietly walked out of the office door.
We all were hysterical over the joke and animatedly discussed whether or not we should
tell the man when he returns the next day. But, ...he didn't. Then, after 3 days, we began to
worry... had we gone too far. Nervously, I approached the Personnel Manager and inquired
about the missing man. "Oh, not to worry" was his reply..."He called the other day and
advised us that he is now aware that he has a very serious drinking problem and admitted
himself to a detox clinic for treatment and rehabilitation. His co-worker will be starting
next week to continue the work until he rejoins us."
I remember that Panic Alarm (I was a mere child back then) and may still have the issue somewhere in the basement! As I recall it had a neon lamp relaxation oscillator for the sound and a tube (50C5) as the amplifier, and a standard base red light bulb to attract the innocent. You had to poke a paper clip through a hole in the case to hit the off switch.
I am reminded of a circuit by Bob Pease, if I remember correctly, to make a member of staff at National talk in a softer tone. It was an audio noise generator and as the voice grew louder so did the audio disturbance forcing the speaker to raise his voice above the noise in a positive feedback loop. Must've been awfully noisy while "training" the offending party!
I am sure he described this in one of his columns many years ago.
Here's one from years ago. One of our system engineers was on business travel and somebody emptied out his sliding desk drawer -- the shallow one where he kept his pencils, calculator, etc. -- and lined it with a sheets of plastic from cut up trash bags. Taped up the plastic nice and tight, then filled the drawer with water to within a millimeter of overflowing...then carefully closed the drawer :)
I can remember a couple more: The "Little Jiffy Fuse Blower" is a small box with a nice label, a heavy duty pushbutton and a wall plug. Pushing the button connects hot to neutral. If you leave it lying around the lights will eventually go out. Also, back in vacuum tube days some guys would leave a charged metal can capacitor on their desk.
Good practical joke! Poor Tom, he was just trying to learn the new products in his own way.
Reminds me of a Popular Electronics magazine construction article back in the 1960's called the "Panic Button". If a victim pushed the button the resulting sound made him he wished he hadn't. A version of this was used on a Candid Camera episode.
Also reminds me of a retail store I once worked in. Often this guy would come in, head over to the CB radio display, grab mics, and holler "Breaker, Breaker!"
A new product called a "Foghorn/Loudhailer" became available, had a PTT (push-to-talk) mic, a powerful audio amplifier about 20 watts IIRC, and a trumpet speaker, was intended for use on boats. We set it up on a display shelf, powered, speaker pointing at the customer, and with the mic gain set to max. When that guy spotted it he keyed the mic but did not get a chance to holler "Breaker!". Instead the acoustic feedback through that trumpet speaker blasted him.
After that he left the mics alone.