Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Bypassing regulatory locks, hacking AirPods and Faraday cages

lagrangepoint.substack.com

Post reply on HN
Print view View original

111–120 of 202 posts

Re: Bypassing regulatory locks, hacking AirPods and Faraday cages

#111

Post by jrockway »

RF_Savage wrote: post #110
rollulus wrote: post #108

Earlier quoted context omitted.

> Microwaves output no power during the zero crossing of the AC line Why is this? Do microwaves by design modulate their 2.4gHz on top of 50/60Hz?

The magnetron needs about -4.4kV to work and food does not care about the purity of the signal, only net energy delivered. So the transformer based microwave oven power supplies have a 2.2kV transformer and then double that to 4.4kV for the magnetron. There is no filtering or smoothing, as those parts would cost money and present a danger to the service technician. So the voltage feeding the magnetron is not even sin…

Yup, exactly. Compare the price of a PC power supply, which outputs a very smooth constant voltage, to a microwave oven. The microwave oven is cheaper, and uses all 1800W of your circuit. A DC power supply that does that is much more expensive.

It is truly amazing how cost-optimized microwave ovens are.

Re: Bypassing regulatory locks, hacking AirPods and Faraday cages

#112

Post by jrockway »

subarctic wrote: post #106
jrockway wrote: post #101

> Since WiFi and a microwave operate at the same frequency (2.4GHz), we ran our leaky microwave at full power to block out any persistent network signals in the air. Incidentally, WiFi tries to intentionally avoid this interference. Microwaves output no power during the zero crossing of the AC line that's driving it, and in this interval, there is no signal in the air to jam things. WiFi listens before sending (so as…

Whatever the theoretical analysis tells you, I've been able to reproduce a microwave interfering with a wifi signal with at least one microwave and router. I've had other times where it didn't have a noticeable effect though.

The key to happiness in WiFi is that all the stations have to "hear" each other, or the listen-before-talk algorithm can't work and you end up stepping on valid transmissions that you can't hear. This ruins it for the stations that are the targets of that transmission but can also hear the first station. This is why WiFi tends to degrade at longer ranges; with a topology like , both computers can hear the access point, but can't hear each other. This means that they step on each other when talking to the access point; when this happens, the access point sees the sum of the two signals which is has to discard as garbage. As a result, whenever you see enterprise WiFi that actually works, you'll probably be able to see a ton of access points covering a large room. This is so that they can transmit at low power, causing devices in the above topology to roam to a different access point before they enter the failure mode of not hearing other stations connected to that access point.

Now that I think about it, in OP's case, it's quite possible that the iPad can "hear" the microwave, but the access point can't, so the access point will send out its SSID broadcast while the microwave is interfering. This is great because you WANT that packet to get corrupted. So maybe the microwave does help!

Re: Bypassing regulatory locks, hacking AirPods and Faraday cages

#113

Post by greggsy »

tzs wrote: post #47

> Hearing aids typically cost anywhere from ₹ 50,000 to upwards of ₹ 8L depending on the correction capability For those who don't recognize the ₹ symbol it is the symbol for the Indian Rupee and an "L" after a number means 100,000, so ₹ 8L is ₹ 800,000. At current exchange rates that puts hearing aids in India from $600 to upwards of $9,500. AirPods Pro 2 are ₹ 24,900 ($295).

I’m not across the scope of hearing aid technology, but what does the product at that upper tier actually look like, and how much does it cost in another country?

I’m envisioning some highly specialised and tuned implant at that price.

Re: Bypassing regulatory locks, hacking AirPods and Faraday cages

#115

Post by eliasdaler »

This showcases why free software is important. Geo-locking is a such hostile practice which makes zero sense here.

If the software/firmware was free and open, you’d be able to patch out/disable the geo-lock. But it probably wouldn’t be there in the first place…

Re: Bypassing regulatory locks, hacking AirPods and Faraday cages

#116

Post by ilt »

lathiat wrote: post #104
_rs wrote: post #97

Earlier quoted context omitted.

I suppose the difference is 1st party support for creating the audiogram, plus the clearance from the US gov to market it the way they want as OTC hearing aids

It also applied the same profile to both ears, which matters for some. My hearing loss is highly asymmetric.

Does it still do that? I understand it had problems with asymetric hearing loss earlier.

Re: Bypassing regulatory locks, hacking AirPods and Faraday cages

#117

Post by RobotToaster »

jrockway wrote: post #101

> Since WiFi and a microwave operate at the same frequency (2.4GHz), we ran our leaky microwave at full power to block out any persistent network signals in the air. Incidentally, WiFi tries to intentionally avoid this interference. Microwaves output no power during the zero crossing of the AC line that's driving it, and in this interval, there is no signal in the air to jam things. WiFi listens before sending (so as…

So two leaky microwaves on different mains phases would block (2.4ghz) wifi?

Re: Bypassing regulatory locks, hacking AirPods and Faraday cages

#118

Post by PeterStuer »

Reminds me on how I setup laptops these days for geodisplaced vpn enjoyment.

Have the laptop on the vpn even during OS install. Never run the vpn client on the laptop. Never connect to any other network. Use the target's localisation (language, kb, timezone) during install. Have a dedicated browser with detailed location features turned off for your target sites.

Post reply on HN