Devices
Why your phone slows down, and which explanation is actually true
Several real mechanisms get collapsed into one conspiracy. Separating them explains what you can fix and what you cannot.
Mikkel Aas
Editor, Tech Behind Things
Mikkel edits Tech Behind Things and has taken apart more devices than he has successfully reassembled.
Contact Mikkel through our contact page — mark your message for their attention and it will be passed on.
38 articles
Data & Privacy
End-to-end encryption: what it protects and what it never did
The contents of your messages and the fact that you sent them are two different secrets, and only one is usually covered.
Devices
How a touchscreen knows it is a finger and not a raindrop
Capacitive sensing measures a change in an electric field, which explains gloves, water, screen protectors and phantom taps in one…
Networks
Bufferbloat: the reason your connection stalls while the speed test passes
Buffers were added to prevent packet loss and ended up hiding congestion until it turned into seconds of delay.
Networks
Why you cannot reach your own devices from outside your house
Address exhaustion pushed most homes behind shared translation, and the consequences show up in gaming, cameras and remote access.
Networks
Bluetooth audio makes you choose two out of quality, latency and battery
A wireless link with a fixed budget has to give something up, and every codec makes that decision differently.
Power & Batteries
Why the last twenty per cent of a charge takes so long
Charging a lithium cell has two distinct phases, and only the first one is fast. The slowdown is chemistry, not throttling for its…
Software
Why some files compress to almost nothing and others refuse
Compression removes predictability. A file with none left has nothing to give, and that limit is mathematical rather than a…
Home Tech
How an induction hob heats the pan and not the surface
A changing magnetic field induces currents inside the metal of the pan, which is why the glass stays cool and why some pans do…
Home Tech
How a smart speaker listens for its name without recording the room
A tiny model running locally on a low-power chip watches for one pattern, and only what follows it is sent anywhere.
Home Tech
Turning the thermostat up does not heat the room any faster
A thermostat is a switch with a target, not a throttle, and the belief that it is a throttle wastes a great deal of energy.
Home Tech
Two kinds of smoke alarm detect two different kinds of fire
Ionisation and photoelectric sensing respond to different particle sizes, which means the type you fitted decides which fires you…
Data & Privacy
Why a website cannot tell you your own password
A correctly built service never stores what you typed, only a one-way transformation of it, and that design decides what a breach…
Data & Privacy
What an app permission actually grants, and for how long
Permission prompts describe a category, not a specific action, and the gap between those two is where most surprises live.
Data & Privacy
Your phone knows where it is without using GPS at all
Positioning usually comes from databases of nearby wireless networks, which is faster, works indoors, and creates a different…
Data & Privacy
Face and fingerprint unlock are convenience features with a security trade
Biometrics are excellent at making strong protection tolerable and poor at being secrets, because you cannot change them.
Data & Privacy
Not all two-factor authentication is equal, and codes by text are the weak one
The second factor exists to survive a stolen password, and the methods differ enormously in whether they actually do.
Data & Privacy
The padlock in your browser means less than most people think
A certificate proves the connection is encrypted to the name in the address bar, and says nothing about who is behind it.
Data & Privacy
What telemetry actually sends, and why software collects it
Usage data genuinely improves products and is also the least examined category of collection in most software.
Data & Privacy
What actually happens when you delete something
Deletion usually removes a reference rather than the data, and the copies you did not make are the ones that persist.
Networks
The faster Wi-Fi band is the one that cannot get out of the room
Reach and capacity are traded against each other by physics, not by firmware. A house usually needs both bands doing different jobs.
Networks
The distance to the server sets a delay no upgrade can remove
Four separate delays are added together every time you click, and only one of them responds to paying for a faster line.
Power & Batteries
Two devices argue about voltage before any fast charge begins
A charger starts at a low safe default and stays there unless a conversation persuades it otherwise. Most slow charging is a failed…
Power & Batteries
Why a smoke alarm suits a disposable cell and a camera flash does not
Single-use and rechargeable chemistries fail in opposite ways. One leaks its charge away over months, the other leaks its contents…
Power & Batteries
A capacitor charges in seconds, and that is not the advantage it sounds like
Storing charge on a surface rather than in a reaction makes it fast, durable and almost unbelievably bad at holding very much.
Software
Almost everything on your screen was fetched before you asked for it
Caching is a bet that you will want the same thing twice. Every layer of a computer makes that bet, and the losses are invisible.
Home Tech
A dehumidifier heats the room it is drying
Every watt it consumes ends up as warmth in the same space, and the water in the tank arrived by being chilled below its dew point.
Home Tech
Suction is airflow, and the filter decides how much of it you get
Two different measurements get called suction, they trade against each other, and the one that matters changes with what you are…
Home Tech
How a filter catches particles smaller than the gaps in it
A high efficiency filter is not a sieve. Four different physical effects capture particles, and the hardest ones to catch sit in…
Home Tech
Why a doorbell camera catches people leaving and misses them arriving
A battery-powered camera spends most of its life asleep, and waking up, connecting and starting to record takes longer than a…
Data & Privacy
Blocking cookies did not stop tracking, it changed the method
Your browser answers dozens of ordinary technical questions on every page, and the combination of those answers is frequently…
Data & Privacy
Metadata says who, when and where, and it is rarely encrypted
Strong encryption protects what was said. The record that a conversation happened, between whom and for how long, usually travels…
Data & Privacy
Your photographs carry a second file inside them
Every image holds a block of information the camera wrote about itself, the moment and often the exact place, and it travels with…
Data & Privacy
A passkey removes the secret you could be tricked into giving away
There is no shared string to type, leak or hand to the wrong site. The device signs a challenge, and the signature only works for…
Data & Privacy
Nobody sold your name, they sold everything attached to it
The value is not in any single record. It is in joining scattered records together until they describe one household with…
Data & Privacy
Your television is quietly identifying what is on its own screen
It does not need to know the source. It samples what it displays, matches the sample against a reference library and reports what…
Data & Privacy
The sender knows you opened it before you finish reading
A message that loads anything from the internet is making a request, and a request is a report of exactly when and roughly where…
Data & Privacy
Why adding one lawful key to encryption weakens it for everyone
The technical objection is not that access is impossible. It is that a mechanism for guaranteed access is a mechanism that must…