Why are mains power computer mice, keyboards and headsets very rare or non-existent?

[General Zod]

Ergonomics is a simple reason you don't have everything plug into a power outlet. You tend to have no more than two outlets in a given room and even with power strips having all those cables routed to the wall creates an ugly mess. This simply isn't workable in any sort of environment where you need to be productive. Otherwise instead of being one or two feet every mouse cable would have to be long enough to reach a power strip. In a environment where you need as much space as possible this is unacceptable.

[Archinist]

The decibel output of headphones is deliberately limited to try and prevent people from suing the manufacturer for damaging their hearing.

Good quality headphones actually require less power than typical consumer headphones, because they have a higher sensitivity, which means that they convert electrical energy into sound pressure more efficiently. Note that 'expensive' does not imply 'good', there are a lot of crap headphones sold on brand name.

I thought they usually have more speakers, and larger speakers than small cheaper ones, thus using less power? I mean, how does a tiny 1w speaker on each side use more power than several small 5w (or however many watts they use) speakers on each side?

[Jaepheth]

With headphones you have low impedance and high impedance models.

High impedance require an amplifier and more power to get quality sound out of, but are less susceptible to noise.
Low impedance require less power to drive making them better for consumer electronics, but they also respond to any static coming over the line.

Sound equipment has a lot of variables. For example, if they're using powerful neodymium magnets then it won't require much current to get a response even if it's physically bigger than a less efficient speaker.

If your $200 headphones are sounding like crap then you may need an amplifier. Or you may need a better source, or they could be crap headphones you paid $200 for.

TL;DR: You wouldn't make a pair of headphones that plug into the wall. You'd plug your amplifier into the wall and your headphones into the amp. And there are already plenty of amplifiers on the market. My amplifier is USB powered. Because that's all I need to drive a single pair of 250ohm headphones.

[Tribble]

What is so bad about this post? I'm not an engineer or electrician, so how should I automatically know that 240V mains power PC peripherals would obviously be a bad idea?

Because it should be common sense? Why would you put 240v through something that works just as well with far less voltage? I'm also not an engineer, scientist nor electrician, yet it seems kind of obvious that something like a mouse or keyboard isn't going to become suddenly far better simply because you throw a lot more electricity at it. That's not much better than assuming that "more heat = faster cooking time" is always a good thing: sure you could just pour gasoline all over your turkey and throw it into your fireplace instead of sticking it into the oven, and I'm sure it's going to cook faster, but it's probably not going to turn out the way you want it too.

I mean as long as they put a warning in the instruction manual to not pour coke or water onto the keyboard/mouse/headset as people love to do, and also put some extra-bolding on the loudness warning, everything should be fine safety-wise.

Again, not an engineer, electrician or scientist, but to me common-sense would be that whoever built these things had more safety features in mind than "hope the buyer reads the manual and nothing bad happens". As others have pointed out, there is no real gain in having 240v running through your keyboard and mouse, so the common sense solution would be to only run as much electricity as is needed, not dump as much electricity into it as possible.

I mean some people heat their drinking/bathing water by putting a live 240V metal rod connected directly to the power plug straight into a water bucket.

A) that's heating a bucket of water, not running a keyboard / mouse. It's been awhile since I've been in highschool, but IIRC it actually takes quite a bit of energy to heat up water when compared to a lot of things. I can't think of any reason why you'd need 240v to power your mouse.
B) I imagine that it would be generally better to just use something like a kettle / stove, microwave* or a hot water tank if that's available
C) Correct me if I am wrong here, but I don't think that's the safest way to heat water. There is no way to control the temperature of the water (if you're not monitoring the water carefully you could easily overdo it and burn yourself), there's no way to prevent you from accidentally putting your hand or other body part into the water and/or touching the metal rod (which risks electric shock and/or burning), and there is no way to turn the metal rod off apart from unplugging it. A kettle, microwave* and hot water tank all have the ability to manage those things a lot better than a 240v metal rod being stuck into a bucket of water. Yes it can be used in a pinch, but I personally wouldn't want to rely on it as my primary source for heating water. At the very least I'd want said metal rod to also include a thermostat so that I can set the temperature of the water, some kind of circuit breaker to immediately kill it if there's a short, and some way to keep my hands from making contact with the metal.

Or maybe just a souped up version of this:



Yes, that's a heated water bucket. Rarely been to a barn so I've never seen one of these before, it looks kind of neat.

*you have to be careful to avoid superheating the water with the microwave though. I'd still say its safer than the metal rod, if only because you won't be able to accidentally stick your hand in the microwave while it's on (unless it's broken) and it will turn off when finished.

I thought we were going to see star trek brought up as an example of this principle of mains powered keyboards at work...

Sure, why not have a quick montage:



























Generally speaking, it's probably not the best idea to be running plasma conduits from the warp drive directly through your keyboards.

[aerius]

Generally speaking, it's probably not the best idea to be running plasma conduits from the warp drive directly through your keyboards.

But how would the keyboards keep up with Data's superhuman typing speed without all that power? How?
(yes, this is sarcasm, in case anything thinks I'm completely intoxicated)

[General Zod]

Generally speaking, it's probably not the best idea to be running plasma conduits from the warp drive directly through your keyboards.

But how would the keyboards keep up with Data's superhuman typing speed without all that power? How?
(yes, this is sarcasm, in case anything thinks I'm completely intoxicated)

Timey wimey wibbly wobbly.

Maybe they bounce the graviton particle beam off the main deflector dish.

[Executor32]

If your $200+ headphones aren't loud/insulated enough to block out external noise, either you bought overpriced shit-quality headphones like Beats, or you really did get high-quality cans from a respectable brand but stupidly went with the highest impedance you could find because more=better, amiritе? Either way, you spent too much for what you're looking for out of headphones.

Case in point, I have a set of Sennheiser HD 280 Pros, which have an impedance of 64Ω. With the volume halfway up on my phone, let alone my computer, you could probably set a bomb off in the next room and I'd be none the wiser. Even without an audio source playing, they attenuate background noise by around 30 dB. They only cost me $100.

[Zixinus]

An addamantum that I didn't say before because I wanted to check first.

No, my hearing is fantastic for general daily use, I can hear everything that I'm supposed to perfectly fine, so if there is damage it is completely unnoticeable and therefore is not damage but just normal wear and tear.

Hearing loss can be gradual from long exposure to loud noise. If you have been listening to music and other things as routinely at high volume (rather than just enough to hear it) you may likely have it. It is not always noticeable but it will happen. This is a regular problem for people that work in loud environments.

[Starglider]

High impedance require an amplifier and more power to get quality sound out of, but are less susceptible to noise. Low impedance require less power to drive making them better for consumer electronics, but they also respond to any static coming over the line.

High impedance headphones do not use more power. In fact they tend to be more sensitive and actually use less power. High impedance headphones require more voltage, but operate with (much) lower currents. They aren't normally used with battery or USB powered equipment because the necessary step-up transformer or converter increases cost (and to some extent, weight). This is exactly the same as a 60W car headlight requiring 5 amps, because it is running off a 12V battery, whereas a 60W domestic bulb requires only half an amp (on US 120V power). The car headlight is low resistance, the domestic bulb is high resistance, but they have the same power rating.