Some decades ago when I was still an engineering student, my team had to present an electronic assignment. The damn circuit didn’t work, no matter what I did. So I decided to go ask the teacher for advice. I walked away a couple of meters, when my teammates told me that the circuit finally started working. As soon as I went back, it failed again. We soon determined that it failed only when I was near it. My teammates presented the assignment while I was at the other side of the lab. We passed the assignment, and sure enough, when I approached again to pick up my things, the damn circuit stopped working again.
It could be you wore the kind of clothes - certain shoes, wool pullovers, clothes made of certain plastic fibers - that makes one accumulate static electricity, so you literally had a charge different from the rest (did you have a tendency to get a shock when you touched large metalic objects or other people?)
Or maybe you were the biggest person on the team and hence caused the biggest electromagnetic shadow on the surrounding electromagnetic radiation (nowadays we live surrounded by radio sources). A similiar effect would happen if you had a less dry skin and hence more conductive than your colleagues (was this, for example, early morning after you took your daily shower).
Anyways, somewhere in that circuit was a wire which was unconnected and led to the gate side of a transitor, probably a Mostfet. If you were using a microcontroller in it, you might have left an I/O port enabled that was not physically connected to anything so its value could easilly flip merelly from electromagnetic interference and that day you just happened to have the biggest electromagnetic footprint (due to static charge, body size and/or body conductivity) around.
For fun it’s not hard to make a circuit that “detects people closeby” using a transistor or microcontroller I/O port connected to a wire that goes nowhere with the other side set up to light or not an LED depending on the input signal, which detects people because them being close or not alters the electromagnetic radiation that goes into that wire (an unconnected component pin also works, but it’s more sensitive with a bit or wire). The simple version is not exactly reliable, but it’s pretty spooky when it works.
Some years ago, I (GLS) was snooping around in the cabinets that housed the MIT AI Lab’s PDP-10, and noticed a little switch glued to the frame of one cabinet. It was obviously a homebrew job, added by one of the lab’s hardware hackers (no one knows who).
You don’t touch an unknown switch on a computer without knowing what it does, because you might crash the computer. The switch was labeled in a most unhelpful way. It had two positions, and scrawled in pencil on the metal switch body were the words ‘magic’ and ‘more magic’. The switch was in the ‘more magic’ position.
I called another hacker over to look at it. He had never seen the switch before either. Closer examination revealed that the switch had only one wire running to it! The other end of the wire did disappear into the maze of wires inside the computer, but it’s a basic fact of electricity that a switch can’t do anything unless there are two wires connected to it. This switch had a wire connected on one side and no wire on its other side.
It was clear that this switch was someone’s idea of a silly joke. Convinced by our reasoning that the switch was inoperative, we flipped it. The computer instantly crashed.
Imagine our utter astonishment. We wrote it off as coincidence, but nevertheless restored the switch to the ‘more magic’ position before reviving the computer.
A year later, I told this story to yet another hacker, David Moon as I recall. He clearly doubted my sanity, or suspected me of a supernatural belief in the power of this switch, or perhaps thought I was fooling him with a bogus saga. To prove it to him, I showed him the very switch, still glued to the cabinet frame with only one wire connected to it, still in the ‘more magic’ position. We scrutinized the switch and its lone connection, and found that the other end of the wire, though connected to the computer wiring, was connected to a ground pin. That clearly made the switch doubly useless: not only was it electrically nonoperative, but it was connected to a place that couldn’t affect anything anyway. So we flipped the switch.
The computer promptly crashed.
This time we ran for Richard Greenblatt, a long-time MIT hacker, who was close at hand. He had never noticed the switch before, either. He inspected it, concluded it was useless, got some diagonal cutters and diked it out. We then revived the computer and it has run fine ever since.
We still don’t know how the switch crashed the machine. There is a theory that some circuit near the ground pin was marginal, and flipping the switch changed the electrical capacitance enough to upset the circuit as millionth-of-a-second pulses went through it. But we’ll never know for sure; all we can really say is that the switch was magic.
I still have that switch in my basement. Maybe I’m silly, but I usually keep it set on ‘more magic’.
1994: Another explanation of this story has since been offered. Note that the switch body was metal. Suppose that the non-connected side of the switch was connected to the switch body (usually the body is connected to a separate earth lug, but there are exceptions). The body is connected to the computer case, which is, presumably, grounded. Now the circuit ground within the machine isn’t necessarily at the same potential as the case ground, so flipping the switch connected the circuit ground to the case ground, causing a voltage drop/jump which reset the machine. This was probably discovered by someone who found out the hard way that there was a potential difference between the two, and who then wired in the switch as a joke.
Your capacitance is probably weird. Are FM radios you tuned also very likely to go to static when you walk away? (also possible the cause was something you were wearing or carrying)
Some decades ago when I was still an engineering student, my team had to present an electronic assignment. The damn circuit didn’t work, no matter what I did. So I decided to go ask the teacher for advice. I walked away a couple of meters, when my teammates told me that the circuit finally started working. As soon as I went back, it failed again. We soon determined that it failed only when I was near it. My teammates presented the assignment while I was at the other side of the lab. We passed the assignment, and sure enough, when I approached again to pick up my things, the damn circuit stopped working again.
It could be you wore the kind of clothes - certain shoes, wool pullovers, clothes made of certain plastic fibers - that makes one accumulate static electricity, so you literally had a charge different from the rest (did you have a tendency to get a shock when you touched large metalic objects or other people?)
Or maybe you were the biggest person on the team and hence caused the biggest electromagnetic shadow on the surrounding electromagnetic radiation (nowadays we live surrounded by radio sources). A similiar effect would happen if you had a less dry skin and hence more conductive than your colleagues (was this, for example, early morning after you took your daily shower).
Anyways, somewhere in that circuit was a wire which was unconnected and led to the gate side of a transitor, probably a Mostfet. If you were using a microcontroller in it, you might have left an I/O port enabled that was not physically connected to anything so its value could easilly flip merelly from electromagnetic interference and that day you just happened to have the biggest electromagnetic footprint (due to static charge, body size and/or body conductivity) around.
For fun it’s not hard to make a circuit that “detects people closeby” using a transistor or microcontroller I/O port connected to a wire that goes nowhere with the other side set up to light or not an LED depending on the input signal, which detects people because them being close or not alters the electromagnetic radiation that goes into that wire (an unconnected component pin also works, but it’s more sensitive with a bit or wire). The simple version is not exactly reliable, but it’s pretty spooky when it works.
https://catb.org/jargon/html/magic-story.html
I bet that “magic” switch was set up by a geek with an electronics background to take the piss of the ones without such a background.
Yessss, I came to the comments to see if somebody else posted it.
Your capacitance is probably weird. Are FM radios you tuned also very likely to go to static when you walk away? (also possible the cause was something you were wearing or carrying)
maybe you wore something that gave you just enough static charge to cause problems?