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Running Tesla Model 3's computer on my desk using parts from crashed cars

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Re: Running Tesla Model 3's computer on my desk using parts from crashed cars

#21

Post by toast0 »

londons_explore wrote: post #12
serf wrote: post #8

Earlier quoted context omitted.

you're correct. a '12v ICE' alternator generates up to 14.8-15.2v. Most automotive stuff can operate between 9ish-16ish-v , of course totally depending on the product. of course this is just a modern interpretation. older stuff runs at 6v and some weirdo offbeat cars have a 24v/48v rail sitting around somewhere. Cop cars often had alternators that put out weird voltage ranges for certain equipment, or dual 12v for hi…

Whilst cranking, an ICE car will drop to around 6 volts (then maximum power is extracted according to thevenim's theorem). That means all computers etc will work at 6v.

> Whilst cranking, an ICE car will drop to around 6 volts (then maximum power is extracted according to thevenim's theorem).

> That means all computers etc will work at 6v.

Not necessarily all of them. Plenty of stuff will drop out while cranking; hopefully not the computers that run the fuel injection and ignition, though.

Re: Running Tesla Model 3's computer on my desk using parts from crashed cars

#22

Post by girvo »

slfnflctd wrote: post #18
girvo wrote: post #10

It's funny to hear LVDS be described as an "automotive" cable when all of my run-ins with it are for connecting laptop displays to their main-boards! (though that has a very different connector on it, and its a very general term for the signalling protocol from what I remember)

Not saying there's anything wrong with your perspective (lots of terms get in muddied waters, it's common and not a problem if everyone is on the same page), but this is what I just found on Wikipedia: "Early on, the notebook computer and LCD vendors commonly used the term LVDS instead of FPD-Link when referring to their protocol, and the term LVDS has mistakenly become synonymous with Flat Panel Display Link in the…

Yeah I saw that too which is why I posted my comment, it's surprising to me :) LVDS for display cables was an incredibly term in that context. Even still is sometimes despite them mostly being eDP (embedded-DisplayPort) now, which is quite incorrect hah

Re: Running Tesla Model 3's computer on my desk using parts from crashed cars

#23

Post by bluGill »

londons_explore wrote: post #12
serf wrote: post #8

Earlier quoted context omitted.

you're correct. a '12v ICE' alternator generates up to 14.8-15.2v. Most automotive stuff can operate between 9ish-16ish-v , of course totally depending on the product. of course this is just a modern interpretation. older stuff runs at 6v and some weirdo offbeat cars have a 24v/48v rail sitting around somewhere. Cop cars often had alternators that put out weird voltage ranges for certain equipment, or dual 12v for hi…

Whilst cranking, an ICE car will drop to around 6 volts (then maximum power is extracted according to thevenim's theorem). That means all computers etc will work at 6v.

The specs say no less than 6volts. In the real world when the temperature drops down to -70F or colder and batteries get old the voltage goes well below that: deal with it.

Re: Running Tesla Model 3's computer on my desk using parts from crashed cars

#25

Post by LikeBeans »

silisili wrote: post #6
LikeBeans wrote: post #3

Very cool. Over a year and a half ago I installed a towing brake controller in my Tesla Model Y. Found the location of the plug, how to access and the pinout online (confirmed via a voltmeter..) so the car's side felt straight forward. But then I needed to find a brake controller that can work with the higher voltage (14.4v vs the normal 12v). Then built a cable from the brake controller to the connector that plugs i…

> But then I needed to find a brake controller that can work with the higher voltage (14.4v vs the normal 12v) Not understanding this sentence. Most running ICE vehicles product closer to that 14.4 than 12v. I think a standard controller would have worked fine?

You are probably right. Surprisingly the first controller I tried didn't work. I assumed the voltage was too high since it worked in my other (much older) car. I found a reference online of people that tried a particular brand/model and that's what I went for. Thankfully my car isn't the model with the internal 18v battery.

Re: Running Tesla Model 3's computer on my desk using parts from crashed cars

#27

Post by bluGill »

I used to work for a company that made third party scan tools. We had racks of ecus disconnected from the car with just a diagnostic connector and power. nothing got to a real car without first trying it on the rack. I remember on time we figured out a bmw (pre obdii) had the bytes offset from the standard documentation (it was a semi-standard protocol that some other cars used at the time), we went from we communicate but nothing is wrong to a very long list of dtcs on that controller. (All our competitors also showed nothing wrong, but the official bmw tool showed dtcs)

Re: Running Tesla Model 3's computer on my desk using parts from crashed cars

#28

Post by kotaKat »

I'm amused reading the terms and requirements the author mentions in the bug bounty program for researchers gaining root access (under 'Vehicle Targets') - https://bugcrowd.com/engagements/tesla

"To promote further security research, Tesla offers security researchers the opportunity to retain root access on their infotainment system even after their reported vulnerability has been patched. In order to qualify, a researcher must send in a valid report describing a novel way to gain root access on a Tesla infotainment system. Upon confirmation, Tesla will instruct the researcher on how to use their existing root access to enable the researcher SSH feature, along with an SSH certificate for the researcher's public key (tailored to their specific hardware ID). The certificate restricts SSH access to the local diagnostic ethernet link. Tesla may renew the certificate as long as the researcher continues reporting vulnerabilities."

Very neat.

Re: Running Tesla Model 3's computer on my desk using parts from crashed cars

#29

Post by kube-system »

serf wrote: post #8
silisili wrote: post #6

Earlier quoted context omitted.

> But then I needed to find a brake controller that can work with the higher voltage (14.4v vs the normal 12v) Not understanding this sentence. Most running ICE vehicles product closer to that 14.4 than 12v. I think a standard controller would have worked fine?

you're correct. a '12v ICE' alternator generates up to 14.8-15.2v. Most automotive stuff can operate between 9ish-16ish-v , of course totally depending on the product. of course this is just a modern interpretation. older stuff runs at 6v and some weirdo offbeat cars have a 24v/48v rail sitting around somewhere. Cop cars often had alternators that put out weird voltage ranges for certain equipment, or dual 12v for hi…

Even just a "12v" automotive battery itself is mostly dead if if actually reads 12.0V. Fully charged is around 12.6 or 12.7. If a car had an electrical system that actually ran at 12 volts, the battery would always be dead.

"12v" in reference to anything automotive is very much a nominal reference.

Re: Running Tesla Model 3's computer on my desk using parts from crashed cars

#30

Post by flutas »

inventor7777 wrote: post #16
bombcar wrote: post #14

Earlier quoted context omitted.

I thought I saw an HDMI connector, but maybe I was wrong.

Ha! Reading this comment made me curious, so I went back and looked at the article and there does seem to be a full sized HDMI connector. I wonder if it is enabled, or just for Tesla internal testing?

It's only a debug port and not actually HDMI signaling, unfortunately.
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