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Comment by taraindara | Hacker News Reader

I share the sentiment. I want a new car, but only if I can guarantee all telemetry is hard disabled. But I don’t have the kind of money to buy a new car and risk bricking it. Luckily I’m pretty handy, so I’ll have to keep my 2014< cars forcefully running as long as I can.

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I have non concerns about having a built in button to phone emergency services. I don’t even mind if it auto rings in a crash. I’m even happy to provide position to the emergency service in the event of dialing them.

Manufacturers use this capacity as an excuse to push more adtech penny and dime data abuse, knowing half the world will blame the government.

Your cell phone could easily call for help in a crash without the car being involved at all.

Not if I'm unconscious?

iPhones actually can. I'm guessing some Androids have an equivalent.

Apple Watch for sure. It seems like you have been in an accident. Hit this button to cancel or EMS will be called.

Other drivers will phone it in. This isn't a concern for me at all, but I suppose it could be if you lived in a low population area.

other drivers will assume someone else already called it in and drive past

Good god thats a bleak thought, where do you live that people behave like that?!

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

Not when you go off the side into a ditch

From a cellphone’s perspective a crash = extreme acceleration with different vectors vs a dropped phone, they can also listen for broken glass etc. So even with GPS off that’s detectable.

iPhone 14+ and Android 12+ https://en.androidsis.com/How-to-activate-automatic-accident...

Interesting info/link, thanks for sharing.

Generally I read your comment that a dropped phone only hits the floor once, therefore there is only one vector and the car always overturns/flips/turns and therefore there are multiple vectors measurable in the car?

I am not convinced yet, it might be possible without GPS, at least to some degree of error (false positives and false negatives). The info in the link requires GPS to be switched on. hmm

I'll take the risk.

Disabling the antennas is the only way to be sure. There will typically be a coax connection that you can cap with a terminator. GPS can be merged with other radios you might not want to lose but suitable splitters are available.

GPS uses a different frequency and a very weak signal. The antenna is typically separate from the others but it's very small <5 mm¹. It can be on the same board with other antennas with 3…4 cm separation between them. Also, we tested a GSM tracker and it still worked with a mismatched antenna. This was in Eastern Europe where cell tower power is quite strong. You have to completely remove the antenna and terminate its connection to be 100% sure. If you have coax cables with external antennas, you're lucky. The worst case scenario is when they're embedded in the infotainment system with amtennas and everything. This is also a cost cutting measure, so it's very likely to be used. The infotainment system is usually ideally placed under the windshield for undisturbed signal reception. But there is still hope to completely cover its back side and edges with aluminium foil tape.

1. https://learn.sparkfun.com/tutorials/gnss-chip-antenna-hooku...

I thought most would use their “shark fin” on the roof for everything (if there is one but there usually is). Terminating on the other end somewhere with a color coded FAKRA connector.

That's quite far away for the weak GPS signal over RF cable, but they still do it. Or maybe the GPS unit and LTE modem are also in the shark fin or nearby and they use a serial, CAN FD/XL or single pair ethernet connection to it? Another choice is in the center of the dashboard under the winshield or under the mirror.

From teardowns, there’s more than just antennae in those shark fins, so might amplify or LNA or whatever within the shark fin.

>aluminium foil tape

uh-oh

Ford has GPS with FM on the same cable. They have splitters for this arrangement. This is why they transitioned to stubby antennas for better GPS and good enough FM.

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