Check if your IKEA chair is compatible with your screen
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The machine was some laptop mainboard glued to the backside of my monitor, and the USB socket came out at the top of the mainboard. On its way down, the USB cable for the keyboard passed across the whole mainboard. On high load, the mainboard created enough interference to cause the connection to reset, re-hotplugging my keyboard, so the previous setxkbmap call was not effective anymore and i was back to the standard US qwerty layout.
I love when software and the real world have entirely unexpected interactions. And by love, I usually mean hate, especially when I'm the one that has to debug them.
As an example: many backpacking trip stories are type 2 fun.
Turned out to be an overheating issue. The chocolate ice cream was at the back of the store while the vanilla ice cream was at the front, effectively changing how much time the car had to cool down properly before attempting to start it again.
https://www.coolermaster.com/catalog/cases/mainboard-case/fr...
Not long ago, Framework engaged in marketing and promotion campaigns to demonstrate aftermarket uses for their mainboards via direct outreach to popular creators on YouTube and Reddit. I spoke with one of the participants who confirmed that they were sent the mainboard and commissioned by Framework for their project.
Doesn't make any of it less cool, but there's no "secret cult of Framework" driving things, just smart business strategy.
My wifi is on the same breaker as the outdoor outlets so any issues with water intrusion affects the wifi.
Eventually it dawned on me: I sat the laptop, right on top of the VHS deck while running the rips. The VHS head ended up directly under the CPU and HDD, such that, CPU and hard drive activity were interfering with the tape reading! I moved the laptop off the VHS deck and everything worked just fine.
It's such a Rube Goldberg kind of error, I love it.
We had an interference problem at work once, in a VME rack, an I/O board with a particularly large coil was messing with the CPU board, solved by moving the offending board in another slot. The effect was mostly random crashes and reboot though, nothing fancy like a keyboard layout change.
Then the design team would figure out the reason for any resets or operational anomalies (or damaged components) and put whatever additional suppression was needed. Sometimes this required rerouting of traces to reduce coupling or redesign of the ground plane. It's a tricky business and expensive if you want to do it right. I suspect that your average $120 display does not see this kind of testing.
Computer equipment usually does pretty well, especially after installation (when there's good ground path everywhere and it's in a chassis). Between ferrite beads and TVS, there's a pretty good amount of protection, and I've seen pretty few ESD anomalies-- a reset or two when touching connectors long ago is about the extent of it.
RFI and EMC is another matter. When I was operating a 100W 30MHz transmitter indoors briefly, the computers around did all kinds of wacky stuff. Flashing screens, random mouse clicks (from wired mice), transmitting packetstorms on their own, etc.
9 year-old me was delighted to discover that it would start playing on its own when it was near the plasma globe I had bought at a science museum gift shop. I couldn't explain it, but eventually came to a vague understanding.
It was semi-random, mashing together short, distorted sequences from the song bank stored in memory. Being almost recognizable made it more haunting.
I remember bringing this out one night during a sleepover and we all got kind of spooked. Fun times!
If I open the door and grasp for the (metal) edge of it before I start sliding out of my seat I will be grounded and consequently not build up charge as I leave the seat.
For example, we have a few bar stools at home; sitting on one always primes me for getting shocked after getting off it. I figured a few rules, such as never wearing anything isolating on my feet, so I can dissipate charges by keeping one foot on the metal part of the chair; or, failing that, I make sure there's always a metal object in grasping range, which I can use to later discharge in a less painful way.
(Pro tip: don't do the metal discharge thing with the hand you wear rings on, and hold the metal item so it doesn't touch the underside of your fingers - getting a shock through a nerve isn't pleasant at all.)
Another thing: I always keep a metal coat hanger around the bedroom, so that whenever I have to deal with blankets, I can keep "swiping" them to collect charge and then transfer them away by touching something grounded with the coat hanger.
Also: I always have my keys on me when away, in an easily-accessible place, specifically so I always have a metal object I can use to offload static charge in a pain-free way.
Also: over the years I kind of habituated all kinds of subtle behaviors designed to keep me safe from getting shocked by my wife or kids. Basically, if I feel one of them just got charged (e.g. via the blankets or the bar stool mentioned before), or I haven't kept track of their recent movements in a static-rich environment, if there's a need or chance of any kind of physical contact, I instinctively first touch using my elbow or some other pain-minimizing way, just to equalize charges with them. My wife sometimes notices when I do it to her, but fortunately, she is quite understanding.
https://en.m.wikipedia.org/wiki/Transient-voltage-suppressio...
Not to mention that all modern CMOS chips have protection structures on the input (though not really as good as you'd like for something that is randomly handled by charged up humans).
Ehm, can it still be considered "indoors" if it's 100W at 30MHz?
Had a bad incident a few years ago where EMI created by the windshield wiper motors on a large vehicle was causing voltage dips and spikes for our product. We had protection circuitry so that if the incoming voltage was too low, it would shut down our system cleanly.
Another logitech one: I have a g27 steering wheel/pedal set/shifter combo. The pedals plug into the wheel, which also connects to a power supply and USB cable to connect to the computer. If you plug the steering wheel into the power and DON'T plug in the USB cable, metal parts of the pedals "leak" current, and you can feel a painful sensation if you touch the metal with exposed skin.
Personally I remember having a pickup truck with a velour seat. During winter I would slide off the seat at a gas station and the first thing I would tough would be the gas pump handle - ZAAAP. Not what you want at a gas station!
Turns out that the gas piston in her chair (not an IKEA chair in this case) has a bit of "give" to cushion oneself when sitting down, and that compression caused some kind of electromagnetic pulse (I assume?) strong enough to mess with the monitor.
I do wonder if it's perhaps bad for the monitor's lifespan, but it only affected my cheapest one, and with the cause found I can live with it.
Maybe one of the cables is acting as an antenna.
https://www.amazon.com/VSKEY-Anti-interference-Telephones-Eq...
Incredible read on that topic: https://www.ranecommercial.com/kb_article.php?article=2127
Steelcase Criterion / Dell S2716DG
https://news.ycombinator.com/item?id=21978004 [13 comments]
https://news.ycombinator.com/item?id=22036652 [2 comments]
https://news.ycombinator.com/item?id=21976814 [1 comment]
https://news.ycombinator.com/item?id=32515662 [0 comments]
https://news.ycombinator.com/item?id=22014012 [0 comments]
https://news.ycombinator.com/item?id=35737780 [0 comments]
https://superuser.com/questions/1406140/monitor-screen-that-...
Cardboard, for example, is often thought of as a safe material for packaging and handling electronic components (motherboard boxes included). However, it can actually generate a significant amount of static electricity, which can damage sensitive components. Similarly, cotton clothing is often thought of as a safe material to wear in ESD-sensitive environments, but it can actually generate static electricity as well, polyester is generally considered preferred over cotton.
It is a common misconception that electrostatic discharge only causes damage if you can feel it. In reality, ESD can cause damage to sensitive electronic components even if you don't feel anything.
In fact, the damage caused by ESD can be more insidious when it is not noticeable. This is because when ESD is felt, individuals are more likely to take precautions to prevent it from happening again. However, when ESD is not felt, individuals may not even be aware that damage has occurred, leading to potential failures or malfunctions down the line.
I would advise anyone working electronics in any capacity, it's important to keep ESD in mind, as many sporadic issues are more than likely related to electrostatic discharge in some capacity.
And that's why everything comes in anti-ESD bags
and their USB cable that comes with them has a ferrite node.
https://www.amazon.com/AOC-E1659FWU-16IN-Powered-Monitor/dp/...
I cannot tell you how much of a balm this is for my sanity.
I then got a headphone amp on my desk, and noticed the same thing happened every time I switched it on - it had a pretty chunky switch with a satisfying click, but I guess it also kicked out enough ESD to trigger the monitor? Armed with this theory, I replaced the bargin basement displayport cable I was using and now no longer have any screen flickering issues. I don't really know if it's better shielded or something, or I just happen to have moved things around to avoid the majority of the problem.
I wonder how many things we blame on bad hardware/software are actually part of the environment - I know hyperscalers have talked about how ECC failure events are more common than "conventional wisdom", which likely means on non-ECC consumer platforms they are getting relatively regular silent memory corruption events.
The manufacturer does not publish a kit of approved USB devices on its website.
My company is building a chair that doesn't compromise on features for when you need them, but elegantly hides them away when not in use so you won't be tempted every second of the day. We have room in our A round if you're interested.
I also enjoyed the two random occasions where I shot lightning from my hands through the plastic cover of a keyboard and got the electronics into some error state, requiring it to be replugged before it would work again. It was a... power...ful feeling.
This and screaming routers are some of my favorite oddities. An old cisco router that was sitting next to my desk would occasionally "scream" at me. I couldn't describe it any other way, though it was rather faint and you wouldn't hear it with music on. It took some time for ~15-year-old me to figure out that it happened with high rates of small network packets. Could be reproduced with some ping command (I would say with sudo and either a low -i or even -f, but I was a Windows user back then and forgot the relevant flags, or maybe I used hping3.)
I tried this but could not reproduce it by the way.
I honestly think that there's a hidden potential with instrumenting programs with different noises, and being able to listen to them could give you a broad understanding of program behavior without needing to profile or watch logs.
Relevant / you might enjoy: ping -a
I suppose it's some sort of resonance phenomenon.
Naturally, its the speadsheet that I use most often in my duties.
I can occasionally hear such noises from monitors, and have always thought it was some kind of interaction with the phase of the AC power and some kind of internal physics of the monitor. Generally, turning it off and back on again fixes it for me.
But as this article describes, you never know!
I don't honestly think turning it off and back on would do anything, either. I also don't have one of those chairs, nor do I want to buy one and use it to test the theory. But, turning it off and back on again is a simple and easy thing to do that should be reasonably safe for the equipment. There is, after all, a reason why power cycling equipment is often a first step to diagnosing and/or fixing weird problems. :)
When we were teenagers, my friend used to call it "waving a dead chicken". He coined this term to describe the way he would resurrect dead inkjet printers that even I gave up on - by disassembling and reassembling them until they started to work again, while being perfectly open that he has no idea how it could fix the problem, just that in practice it often did.
While this was just a funny term and pretty absurd approach for fixing things (even though it worked!), I took away from it an important realization: the scope of possible causes of a weird, randomly-occuring problem is much larger than I'd normally assume. Over the years, I learned to identify some "outside context" things for computers - ESD, thermals, UV exposure, RF interference, voltage spikes in power lines, devices being almost but not quite connected. Because of that, when in a bind, "waving a dead chicken" may just be called for - in forms of e.g. percussive maintenance (hitting the thing with a wrench), moving things around, switching cables, disassembling, etc.
I'm not entirely certain, but as I recall it switching it off and back on again is not effective against this issue. I've tried, no doubt, but the only thing noted which seems to have an effect (while the screen is active) is removing the text from display.
I have a feeling that grey #A5A5A5 is row-hammering something
You can dial the screen's volume by making the libreoffice window partially transparent (I have that bound to scrolling on the title bar). This is on an Acer 1920x1080 (~23"?) screen from around 2009.
There's specific test images you can find online, designed to maximally stress voltage rails in LCDs. Lower end monitors can actually get enough voltage ripple that the image quality visibly degrades.
I'd use a ground strap designed for wearing while you handle MOSFET ICs.
if you ground your chair directly, it is likely to make YOU be the best circuit to ground when you handle your computer or monitor's AC "mains" (us "uk") power cords.
The resistor will allow static discharge (very few coulombs at very high voltage) but limit the flow of electricity
Directly grounding shouldn't be particularly risky though. It's not uncommon to have a metal desk touching a grounded but not double-insulated chassis or dangling USB cable. And I get the impression that electrical systems are engineered so that users aren't touching live contacts when plugging things in - maybe less so in the case of US plugs.
That said, an RCD/GFCI would help in either case, and might have in the cases of electrocution by faulty phone charger, where current presumably travelled through multiple wires in the USB cable alone.
if your chair is the path to ground, you, via your heart, are the path to ground
I have a mechanical keyboard with a small piezoelectric buzzer, and sometimes I've heard it click, although it's unplugged.
Everything makes sense now D:
My connection:
WASM CODE V3 keyboard -> UGreen USB 3.0 switch -> desktop computer
I don't know which device(s) are at fault but when I get off my (non-Ikea) chair[0], my keyboard sometimes stops working. It's easy to resolve by double-tapping the 'switch input' button on the USB switch, although sometimes the keyboard doesn't work until I click my mouse (or maybe vice versa). Anyway, I've gotten used to it and don't have any motivation to diagnose the issue further.
[0] https://www.haworth.com/na/en/products/stools/very-0.html
A group had done an install at a grocery store. They did in-house testing of the new system, then rolled it out to 1 or 2 lanes to try it out for a few days before upgrading all the lanes with the new system. It was a fairly normal roll-out with a few minor issues, but nothing major.
The day they rolled it out, about 2 or 3 transactions each day started including an extra charge for 10 cents worth of deli meat. This was weird because it would be pretty hard to buy only 10 cents worth of meat, and certainly any deli counter worker who had rung it up would have remembered doing so because it would have been a really bizarre order. None of them had seen such an order come through.
The only thing the transactions had in common was they were paid for with a debit card. Worried about compliance issues and the possibility that there might be a bug in the new card readers, they turned off the debit card functionality. Unfortunately (or fortunately if you work in compliance), it happened again to someone paying with cash. While that was a relief because it meant the card readers were fine, it also meant they had no leads on the problem.
The on-call engineer got called in to work on the problem just before the store closed one night. He checked all the obvious things - problems with the cabling; an incorrect value in the database; some data getting mangled between the cash register and the database; a problem with the scanner; etc. There were no problems he could detect.
In order to keep the last few customers from entering his lane, he moved a shopping cart in front of the lane. In fact he did it to the one next to his as well because he'd be walking around the entire lane working on cabling and such. He crawled under the register to check something things just as the scanner beeped to indicate it detected an item. Sure enough it was for 10 cents worth of meat. He looked around and noticed a mother scolding her child, "Leave to empty carts alone! That lane is closed!" That's when he noticed that the cart had an ad on front of it for some random product. He jiggled the cart, and the scanner beeped again. Another 10 cents of meat.
It turned out the artist who put together the ad thought that the packaging without a barcode on it looked weird, so he grabbed something he had laying around and made a fake barcode that looked similar. By some miracle, the barcode was actually valid and was ringing up 10 cents of deli meat at this store. Mystery solved!
Curiously, I never had someone contact me through https://lunar.fyi/ about this problem so I could not include it in the article. But it is mind boggling how many people have this problem and just now start to realize what is causing it.
I submitted the link here, it’s interesting in its own right: https://news.ycombinator.com/item?id=35744187
Solved by an anti-static floor mat from Floortex. Interestingly only one of the screens reacted this way, the one connected through displayport, HDMI seems more forgiving of electrostatic interferences like this.
Your chair is fine, but your monitor is probably a potato if it can't take that interference.
I turned it on and my screen image started gently moving around.
The fish swam with magnets and having the little tank next to the screen was causing the screen image to move around.
The page unfortunately doesn't explain what this is or how it works. Is it a conductive coating so that it can dissipate the electricity into something else, or does it form a shielding layer instead so that it won't zap stuff?
The problem has gone away.
I don’t have a IKEA chair, currently using a Herman Miller Embody but I do (did) have an IKEA desk. A bamboo worktop, a chest on one side and those weird, A shaped legs on the other.
I also do electronic assembly work at this desk so it's sort of a no-brainer to have the mat, I just had no idea it was also saving me from other weirdness!
Turned to be a result of storing the C64 on a bench under the "large" 26" CRT... When it was kept away from it for a while and had a chance to discharge, everything was ok. But after a while near the TV, it started "typing" gibberish of its own accord.
You might want to look into some extra shielding for your mind. I hear having it blown by static discharge too many times can cause brain damage. ;)
In all seriousness, yeah, this is crazy! IMO, IKEA should either recall and fix, modify the design of, or stop selling these chairs. ESD can seriously damage equipment, and I could easily see there being cumulative effects from something like this.
I have a cordless phone charger where plugging it in sometimes causes my screen to blink black. Since I only unplug/plug it when rearranging cabling, I've never bothered to investigate further.
https://twitter.com/royvanrijn/status/1214162400666103808
It is caused by an electric EMI spike from gas lift office chair. There is even an official Dell issue about it:
https://support.displaylink.com/knowledgebase/articles/73861...
I spent a fair amount of effort trying to figure that one out. Thought it was loose cables, something, but no. I don't have a Markus chair, but my Steelcase Gesture is still capable of making a pretty good amount of static electricity. Once in a while when I stand up if my boom microphone is too close I'll shock myself on it, and most of the time I have to reboot things after that. Haven't permanently killed anything yet, thankfully.
When I plug the machine in, the audio will get all static-y from the built in speakers. It seems to especially happen when I am moving my mouse over a video thats playing - and the playback of videos stutters when pulling the cord in or out of the machine.
Battery life on this machine sucks though... but other than that, its fantastic...
Time to run some experiments
Strangely, if the computer is asleep it will wake up when I zap the ground screw. I'm still wondering how that happens. I guess it gets picked up by the wires which run to the power button? My PC case is pretty awful at EMI shielding like most modern custom PC cases.
After some trial and error I determined the motor likely produces enough interference to trigger the RGBs to turn on. I ended up just cutting the RGB cables because I didn't use them anyway, as I didn't have anything to shield the keyboard (or anything else for that matter) from the motor.
I have a power outlet glued to the desk and since it's a German version the grounding contacts are well exposed, so that, when I wear those sandals, I get up from the chair while holding the grounding contacts.
It doesn't work all the time, specially when I'm also wearing a fleece jacket, because the jacket doesn't discharge over the body. But it helps a bit.
I haven't been able to find anything. The electronics industry ESD mats are rubber for temperature resistance and cleaning, but not comfortable or good for mousing. I found some small cheap mousepads on AliExpress that claim health benefits from grounding but nothing large or high quality.
Looking at the pinouts for HDMI and DisplayPort I see that they both use differential pairs for all the high speed lanes that carry audio and video.
For the lower speed channel for other things such as control functions DisplayPort uses a differential pair. HDMI does not. Does that make HDMI more sensitive to interference?
And only when I'm using HDMI port with a HDMI 3x1 switch. If using the DP port, it seems no such issues.
Solved by adding a "tail" to my chair using a piece of old speaker cable. There is a metal part on the bottom of the chair that the tail can be attached to.
To give people some idea of what they're clicking
Not sure if it is the fabric or the piston, but definitely suspected static since I got the chair.
The screen does not seem to age prematurely because of this.
But my keyboard was weirdest of all, just levitating electrically charged hand over it caused it to restart
And we ruled out loose cables or anything like that