@Crusty..... "I still jump and drop what I am working on when my had brushes something or a strand of copper wire gives me a poke."
Years ago I was tidying up the underfloor cabling in a server room. There were a lot of mains cables that went to underfloor sockets in a part of the floor I could not get to, but had been disconnected from the distribution board and were not live. So I coiled them neatly for further work later.
A couple of days later I was running some data cables in the same part of the floor. The data boss saw the mains cables and got fairly upset. "How can someone leave live cables under the floor?" "Oh, I don't think they're live", I said, "but I better check". And got one of the bare ends and popped it in my mouth. Data guy nearly fainted. I'll never forget his expression....
And I'd love to have been a fly on the wall when you found the "fire alarm" for the lady.....
As an ex fire alarm engineer I seem to have spen half my life looking for errant meeps and other noises. Once while duty engineer I was called out by a client complaining that our fire alarm was keeping her awake, finally traced the noise to a vibrating toy (adult ) in a bedside table. Lady did not know what to say.
On another track, I have been spending the past week rewiring my Sons house electrical supplies. Even thought the neutral and live supply wires were isolated and shorted out to earth, I still jump and drop what I am working on when my had brushes something or a strand of copper wire gives me a poke.
I just received an email from someone who spake as follows:
Hello Max, Years ago I worked for BBC radio in Broadcasting house, London.
We too had such a device to annoy people who were sleeping over in their offices. Ours sounded exactly like one of the corporation phone pagers and bleeped just long enough to wake to victim, who'd "have to" respond to being paged, but stopped before they could get out of bed. I think it went off every 20 minutes to ensure sleep deprivation. I don't believe anyone ever found it and plainly we didn't have enough to do back in those days.
I had my own "meep" experience. Years later I slept over in a church hall in a dodgy part of Leicester. Already I'd opened a fire door and smashed some poor kid on the head who was crouching down spray painting obscenities on the outside, so I was a little jumpy. Half way through the night this wee-oo-oo-eee sound quietly starts.
No obvious source.. eventually I woke up an event organiser who unlocked a store room, inside which the brownies or some such had left their Halloween stuff buried amongst everything else and a toy "musical" lantern's battery had picked that moment to decay far enough that the electronic "off" switch circuit malfunctioned and started operating.... It didn't stay that way for long at 3AM.
Blog Make a Frequency Plan Tom Burke 17 comments When designing a printed circuit board, you should develop a frequency plan, something that can be easily overlooked. A frequency plan should be one of your first steps ...