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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

#101

Post by wpm »

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…

If you don't get PD working, you can always just build a battery pack that charges itself over USB-PD, and outputs 12V. Apparently the built in PSU on the Mini takes 120/240V and outputs nothing but 12.

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

#102

Post by donw »

OJFord wrote: post #36
bitbckt wrote: post #29

Earlier quoted context omitted.

Minor correction: 802.3bt added 51W (Type 3) or 71W (Type 4). 60W isn't a standard power level. Some switches support up to 95W per port with PoH.

Surely they're all ' up to '? It's not 'you must sink this much current or else not compliant'? It seems like a weird thing for TFA to say anyway - my PoE[+] switch was the cheapest 8 port I could get a few years ago on Amazon, and does 30W per port. I don't really understand how you could look into it at all, be willing to attempt the hack, but not use a switch (or injector or whatever) that's capable of powering it…

“By ‘Energy Star’ compliant, we mean that it burns as much energy as the sun.”

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

#103

Post by bob778 »

haswell wrote: post #43
dheera wrote: post #35

Earlier quoted context omitted.

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 is used extensively in network deployments involving rather expensive hardware. I understand the instinct to avoid it at this point, but I’m curious what happened in your case because I’ve never experienced issues. I did work somewhere where someone fried equipment by incorrectly terminating a batch of Ethernet cables thereby sending voltage to the wrong place.

That should only be possible if using non-standard "passive" PoE?

802.3bt has negotiation specifically to prevent faulty cables/devices from being powered.

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

#104

Post by free_energy_min »

crote wrote: post #99
skinkestek wrote: post #93

I've been wondering more than once if we couldn't improve (larger) offices a lot by distributing power pre-transformed so every computer and every screen wouldn't have to include a transformer. I also sometimes wonder why these days, when every new lamp is led, why we don't replace most of the dangerous 230V outlets in new houses with 12V and use 230V only for dishwashers, laundry machines, dryers and that kind of st…

Office equipment doesn't really have "transformers" anymore, everything uses switched-mode power supplies. The way they work, is that they have an output buffer (a capacitor or inductor) and rapidly turn a switch on and off to keep that output buffer at the right level: if the output buffer is below the target voltage, the switch closes and the voltage will start to rise. Once the output buffer rises above the target…

Not op but thanks for the very detailed explanation!

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

#105

Post by NavinF »

dylan604 wrote: post #62
NavinF wrote: post #55

Earlier quoted context omitted.

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.

how does that work if the case is never opened?

You can connect multiple switches in series. Eg one could be a reed switch that detects whether the PC is within 1mm of a tiny magnet in the floor.

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

#106

Post by hnbad »

Alupis wrote: post #69
dheera wrote: post #35

Earlier quoted context omitted.

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.

What kind of PoE Adapter/Hat did you use? From memory, and it's been a few years/models... but the GPIO pins, including the 5V input pin bypassed all of the circuit protection fuses and what-not the normal barrel jack had. It wasn't uncommon for people to roast their RPi with incorrectly done, or poor quality GPIO powering devices.

This is still true. There are ample warnings to be careful when using the GPIO as input because of this. The hat probably passed on some variance that is supported by actual consumer devices and fried the RasPi because it has no protections.

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

#107

Post by dheera »

wolrah wrote: post #67
dheera wrote: post #49

Earlier quoted context omitted.

Sure it could be the RPi hat, but it just means the standard is so complicated that people don't implement it correctly. I wouldn't trust the hat or whatever you call it for Mac Mini.

> Sure it could be the RPi hat, but it just means the standard is so complicated that people don't implement it correctly. Or there are ways to cheap out on a PoE device that may work in some cases but don't fully and properly implement the standard. The standard is widely used in VoIP phones, wireless access points, security cameras, and all sorts of other networked devices that get installed in places that may not…

I mean, one of my hats that fried one of my Pis was a Waveshare hat. This one actually

https://www.amazon.com/gp/product/B0974TK3KD/

PoE operates at a pretty high voltage (almost half of line voltage!) and Waveshare products aren't UL listed.

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

#108

Post by hnbad »

JoeAltmaier wrote: post #42

PoE is a mature technology. Curious that laptops have not been on board.

The more direct problem in my experience is that all kinds of network devices that could reasonably be powered that way don't support it. My Fritz!Box router and repeater don't support it, my Sophos firewall doesn't support it (tho the Sophos XGS can supply PoE it doesn't seem to be able to be powered that way either) and of course the Hue hub and Raspberry Pi can't be powered by PoE either.

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

#109

Post by jondwillis »

shagie wrote: post #90
bravetraveler wrote: post #79

Earlier quoted context omitted.

Thank you for taking the time to follow up! Definitely a bit paranoid - even if I'd prefer to call it robust :) I've had very bad luck in this regard... but haven't honestly used a laptop in probably a decade. I was pleasantly surprised to see my latest (dust-collecting) Lenovo will stop somewhere around 80%! Point being, sure - there are safety things... but batteries are consumables. I like these things to be easy-…

> ... but batteries are consumables. I like these things to be easy-to-replace! Replaceable, consumable batteries often get thrown out in the trash. ... and can set garbage trucks and recycling centers on fire. https://www.waste360.com/safety/lithium-ion-batteries-are-ca... https://www.dispatch.com/story/news/local/2023/02/09/garbage... https://arstechnica.com/gadgets/2022/12/recycling-firm-fined... https://gothamist…

Is the dichotomy here really that we can either have modular batteries, or we can have more intact waste trucks and workers?

However, having just taken an entire stroller out of my shared duplex recycling bin, I know there will never be an ethical way to get 100% of people to care enough to dispose of waste properly.

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