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Hacker mods an M1 Mac mini to receive power over Ethernet instead of AC

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Re: Hacker mods an M1 Mac mini to receive power over Ethernet instead of AC

#51

Post by wil421 »

dheera wrote: post #35
ravetcofx wrote: post #6

" the M1 Mac mini was the perfect hardware to test out PoE, as on idle, the device only consumes 6W. When some load is applied to the internals, that power draw can go up to 40W. After some thorough research, we found out that the maximum throughput of Power over Ethernet was 15.4W " They'll have to bump it up to 802.3bt (Poe ++) which can support 60W. Cool Project though, I've been wanting to mod my Mac Mini m1 to r…

I'm very skeptical of PoE now after 3 PoE adapters killed 3 Raspberry Pis I have. I wouldn't want to risk something more expensive to that shit. At this point I'd rather just have straight up 19V + and - cables bundled together with the Ethernet with some heatshrink around the whole thing to make it look like 1 cable.

I have 13-15 devices running over PoE at my house and all of them work just fine. Everything from the high end Ubiquiti gear to raspberry 3/4 PoE hats. It’s powered by a Unifi 24 port PoE switch.

The only time I had issues was with a 2 mesh APs and sketchy power at a condo that has minor power outages due to thunderstorms. I brought the devices back home and they work fine, the new device doesn’t have an issue. I was curious if a UPS would’ve smoothed the power blips but the new AP restarts and connects just fine.

Re: Hacker mods an M1 Mac mini to receive power over Ethernet instead of AC

#52

Post by monocasa »

mmastrac wrote: post #14
disillusioned wrote: post #4

Having inadvertently plugged a 24v passive PoE live connection into an old 2012 Mac Mini and immediately frying it, this is welcome news!

I thought most modern devices had isolation!

It should be that all devices have isolation. Ethernet is capacitively coupled which keeps you from having to coordinate your power/ground between devices. PoE is the recognition that if the DC levels don't matter because of that required isolation, we might as well not isolate in a power stage before the magnetics and deliver some DC power.

Re: Hacker mods an M1 Mac mini to receive power over Ethernet instead of AC

#53

Post by nomel »

tredre3 wrote: post #10
metadat wrote: post #5

> Thanks to the power efficiency of Apple Silicon, the M1 Mac mini was the perfect hardware to test out PoE, as on idle, the device only consumes 6W. When some load is applied to the internals, that power draw can go up to 40W. After some thorough research, we found out that the maximum throughput of Power over Ethernet was 15.4W and that too over varying voltages, which are details that Ivan had left out when showin…

There are more details in the twitter thread, including a table of PoE standards: https://twitter.com/Merocle/status/1686093369322176512 > What happens when the machine requires more than 15.4W? The voltage will sag and the machine will likely crash!

> The voltage will sag and the machine will likely crash!

USB-C has negotiated power. If they did things right, it should act like a 15W usb adapter, where macOS will gracefully handle the limited power.

Re: Hacker mods an M1 Mac mini to receive power over Ethernet instead of AC

#54

Post by okonomiyaki3000 »

Dalewyn wrote: post #44
lapetitejort wrote: post #20

Earlier quoted context omitted.

The goal of most of these projects are usually to demonstrate that they're possible. Actual use cases are left as an exercise for the reader.

[flagged]

[flagged]

Re: Hacker mods an M1 Mac mini to receive power over Ethernet instead of AC

#55

Post by NavinF »

dylan604 wrote: post #34
r00fus wrote: post #19

Earlier quoted context omitted.

What's the goal of having a MacMini running off an external battery? I mean, it seems less cost effective than just getting a MB Air and not using the screen...

This would be fun for when LEOs come in to take your computer, they can easily keep it powered so all of the decrypted keys stay in memory. Killing power means going back to an encrypted state. In high profile cases for desktops, there's techniques for splicing the power cable to switch to a battery pack. This would make it much easier for the unskilled LEO to take your shit. Cause we all know you're the one they're…

That's why pretty much all desktop and server mobos have a "chassis intrusion" header that you can connect to a sensor/switch. Your machine should wipe keys or reboot if it's opened or moved.

Re: Hacker mods an M1 Mac mini to receive power over Ethernet instead of AC

#56

Post by iseanstevens »

r00fus wrote: post #19
ravetcofx wrote: post #6

" the M1 Mac mini was the perfect hardware to test out PoE, as on idle, the device only consumes 6W. When some load is applied to the internals, that power draw can go up to 40W. After some thorough research, we found out that the maximum throughput of Power over Ethernet was 15.4W " They'll have to bump it up to 802.3bt (Poe ++) which can support 60W. Cool Project though, I've been wanting to mod my Mac Mini m1 to r…

What's the goal of having a MacMini running off an external battery? I mean, it seems less cost effective than just getting a MB Air and not using the screen...

Two large monitors or projectors with Mac mini.

Re: Hacker mods an M1 Mac mini to receive power over Ethernet instead of AC

#57

Post by NavinF »

bravetraveler wrote: post #31
bravetraveler wrote: post #27

Earlier quoted context omitted.

Avoiding the inevitable spicy pillow seems like a good reason An external/easily replaceable battery would be excellent come time to deal with cell age

Does this read like an attack against Apple laptops specifically, or something? Already -2 five minutes after posting it. Leaving as-is for feedback. I don't get the controversy. I could've been a jerk and said just buy a UPS - this is an established concept. Edit: thank you kind souls for restoring the imbalance - carry on :D

No it just reads as kinda paranoid because li-ion cells typically become spicy pillows long after the device becomes obsolete. It's also trivial to avoid by limiting cell voltage. Many devices, most notably iPhones, automatically go into kiosk mode after charging for a few days for exactly this reason: https://support.apple.com/en-gu/HT208710

Re: Hacker mods an M1 Mac mini to receive power over Ethernet instead of AC

#58

Post by sacnoradhq »

jcrawfordor wrote: post #24
evadne wrote: post #21

Earlier quoted context omitted.

Passive PoE is always on Active PoE is negotiated with handshake

Yes, but passive PoE is almost universally at 24v, and per the Ethernet spec (as quoted above) an Ethernet PHY should tolerate 24v fine. This is important as transients from nearby lightning or occasionally even coupling to power cables can produce this kind of voltage. Ethernet connectors are magnetically coupled for protection from these transients. The problem with PPoE in these cases is, I think, not the voltage…

Most people don't realize the huge transient voltages in wires of any significant length that can be induced by nearby electrical storms.

Granted, CAT 5-8 cables are supposed to be twisted pairs and sometimes shielded, but it's imperfect.

PS TIL: https://en.wikipedia.org/wiki/Litz_wire

Re: Hacker mods an M1 Mac mini to receive power over Ethernet instead of AC

#59

Post by NavinF »

dheera wrote: post #35
ravetcofx wrote: post #6

" the M1 Mac mini was the perfect hardware to test out PoE, as on idle, the device only consumes 6W. When some load is applied to the internals, that power draw can go up to 40W. After some thorough research, we found out that the maximum throughput of Power over Ethernet was 15.4W " They'll have to bump it up to 802.3bt (Poe ++) which can support 60W. Cool Project though, I've been wanting to mod my Mac Mini m1 to r…

I'm very skeptical of PoE now after 3 PoE adapters killed 3 Raspberry Pis I have. I wouldn't want to risk something more expensive to that shit. At this point I'd rather just have straight up 19V + and - cables bundled together with the Ethernet with some heatshrink around the whole thing to make it look like 1 cable.

PoE switches and devices are widely used in industry. I suspect your 3 PoE adapters are "passive PoE" consumer crap that doesn't meet spec
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