Electronic Noise Is Drowning Out the Internet of Things | Hacker News Reader

Electronic Noise Is Drowning Out the Internet of Things

spectrum.ieee.org

52 pointsrayiner25 comments

My lab is moving to a new building that was to have wireless flat panel displays on the wall for all professors, each occupying a different band. As we work on RF detectors, this was not ideal, so we (and some other groups) complained and now everyone will have wired displays instead. Small victories...

Wireless flat panels? Thats quite excessive. I bet you cant even get good bandwidth out of them. Wonder if in the near future complex configurations of directed wireless equipment will become a fire hazard lol

How does the ethos of "I can do what I want with my tech" interact with this problem?

I guess it's analogous to saying "it's your stereo. Play what you like, but keep it down after 10PM or your neighbors will report you."

This article also reminds me of the recent discussion on a proposal to make router firmware modifications illegal.

( https://news.ycombinator.com/item?id=10139679 , https://news.ycombinator.com/item?id=9959088 , https://news.ycombinator.com/item?id=10137470 )

Another example: Wireless phone chargers.

Now, the fact that wireless chargers emit RF energy is hardly surprising -- that's how they work -- but I was still surprised when I found that my new charger completely obliterates the AM radio band within a 3' radius.

It's probably caused by induction in the radio's circuits, not by charger emitting radio waves.

Perhaps, but wouldn't that affect FM reception too? I only get interference when tuned to the AM band.

FM capture, perhaps? FM reception is naturally much more resilient to interference so long as the absolute magnitude of the interfering signal is lower.

You can do this kind of thing yourself with a $10 rtlsdr dvbt dongle, NMEA GPS, laptop and various software. The most commonly used is Eartoearoak's rtlsdr-scanner: http://eartoearoak.com/software/rtlsdr-scanner

NW0W has also done a lot of work on mapping powerline interference with rtlsdr dongles in multiple blog posts. An older represenative example is at: http://blog.dxers.info/2015/01/driveby-system-live-on-road.h...

tautology2 showed his visualization implementation + code over at: https://www.reddit.com/r/RTLSDR/comments/2hbjyt/gsm_heatmap_...

omnidirectionality is a luxury. Beam forming and directional scanning listening will become a new norm.

Outdoors on cell towers, yes. Not that helpful indoors. Reflections dominate. Diversity antennas are more useful indoors, because it's rare that both are in a reflection null.

more than 10 years ago some company was doing adaptive beam forming WiFi routers/switches, and what i remember reading about them is that actual direction of the beam for a given connection wasn't necessarily the geographical straight to the other end of the connection, instead it was whatever direction was adaptively found, and that frequently meant very non-straightforward mulitply reflected path. The beauty was that beam power at the "total multi-segmented reflected/bounced" length of the path could still be much higher than onmidirectionally transmitted power even at the lesser distance.

Can you do that without moving parts?

Yes. Phased arrays are just that.

Not very power efficient, though.

Nor space efficient... (depending on the wavelength).

Don't worry about it. The "internet of things" is mostly stuff you don't need anyway. If your toaster has connectivity problems and can't reach the "cloud", and refuses to toast, you probably didn't need it anyway.

How am I supposed to know if my toast is ready? Go over and look? What year is it ... 1934?

I will overlook the conspicuous absence of flying cars, but the year is 2015 and I want an email when my toast is done!

Email? What is this, 1995? Send a notification to my smartphone's app!

It only needs access to: Calendar, Internet, SMS, Profile, Start on Boot, Location, Microphone, Call Log, etc...

One of the things I miss most about college was that the dorm washers emailed me when the laundry was done. Haven't gotten around to setting that up myself.

In Europe we have EMI emission norms, and commercial products have to be tested for this. Either the US is using different products, or the norms are not strong enough ?

As I am involved in defining such standards for industrial applications as an expert at the German national committee, I can tell you, the US has the same standards. Because those standards are harmonized within the IEC.

https://en.wikipedia.org/wiki/Cognitive_radio

Even with these sorts of optimizations, bandwidth is finite.

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