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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

#141

Post by Cthulhu_ »

Topfi wrote: post #132

I have been thinking that PoE is seriously underutilized for what it's capable off. There are so many use cases where one needs both networking and power, yet if you want a one cable solution, you are forced to contend with wireless which, while very reliable in a lot of scenarios nowadays, still can suffer from interference and complicated setup. Sonos and other wireless speaker systems are one of my main examples f…

PoE makes sense if you have a house or building with ethernet cables everywhere, but using your Sonos example, 99.9% of people or more do not have ethernet cables everywhere. They do have regular electricity from an outlet and wifi though.

That said, I'm all for installing ethernet cabling and the like in every room. But it'll likely only happen for new builds.

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

#142

Post by SkeuomorphicBee »

Cthulhu_ wrote: post #139
forgotusername6 wrote: post #126

Earlier quoted context omitted.

Plenty of domestic applications still require higher voltage (well actually power but I presume you aren't suggesting 12V with high current). Vacuum cleaners, hair dryers, anything portable that produces heat. Building houses with low voltage sockets would be really frustrating for people living there. Is the danger of 230V actually significant in this day and age? I wonder how many fires/injuries are caused by 230V…

Fires and injuries at 230V aren't caused by the voltage, but by improper installation and handling. Don't stick forks in outlets, turn the power off when you're working with it, etc. Also, it's not the voltage that kills you, it's the amperage. With regards to the 12V discussion, there's also AC vs DC to consider; AC will flip voltage 60x a second, making your heart go haywire, whereas DC is a continuous jolt, meanin…

> Also, it's not the voltage that kills you, it's the amperage.

A bit off-topic but I never liked that saying, it is kind-of-right but also soo wrong in so many levels. Amperage is not a thing that happens on its own, it is always a result of voltage, voltage is the driving force, so it is the voltage that actively kills you, by forcing amperage through your internals. When the killing happens the voltage is the real murderer, the amperage is just the murder weapon.

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

#143

Post by awiesenhofer »

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…

I have this vision of a future where everything just runs off of usb-c and usb-pd. Even today, expect in the kitchen and the bathroom (refrigerator, washing machine,...) you could totally run most things off of the 240w max. Much more so in an office. It would be so much more efficient than what we have now, and safer. No idea how realistic it is though...

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

#144

Post by NovemberWhiskey »

WWLink wrote: post #77
NavinF wrote: post #57

Earlier quoted context omitted.

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

Definitely disagree. My own anecdotal evidence is that many many laptops left plugged in 24/7 will develop a spicy pillow after a year or two. That includes a set of Apple laptops and hundreds of Dell laptops.

Anecdotally: this has never happened to me despite owning a whole bunch of laptops over the past 25 years or so.

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

#145

Post by NovemberWhiskey »

dheera wrote: post #49
CameronNemo wrote: post #41

Earlier quoted context omitted.

You sure you want to blame poe as a whole instead of the RPI hat?

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.

You're dealing with the same manufacturers that won't even bother to include the USB C termination resistors required to make "USB C" charging ports on their devices work with actual USB-compliant PD. You're talking about the kind of part that's so cheap that adding five of them is going to round down below a penny in your BOM. The kind of manufacturer that, if it had a motto, that motto would be "no corner too cheap to cut".

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

#146

Post by t3rabytes »

awiesenhofer wrote: post #143
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…

I have this vision of a future where everything just runs off of usb-c and usb-pd. Even today, expect in the kitchen and the bathroom (refrigerator, washing machine,...) you could totally run most things off of the 240w max. Much more so in an office. It would be so much more efficient than what we have now, and safer. No idea how realistic it is though...

I pulled the specs for a dual-compressor fridge this morning for an unrelated reason and it only draws 180w... maybe the fridge can run on usb-c too! https://www.bosch-home.com/us/productslist/refrigerators/fri...

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

#147

Post by windexh8er »

consp wrote: post #113
jacknews wrote: post #89

Earlier quoted context omitted.

Exactly, the PC PSU coverts AC to 12v for the PC anyway, so 12v batteries should slot into that scheme, without a separate PSU and inverter.

You would still need a DC to DC converter as lead acids deliver anywhere from 12.8 to about 10v depending on SoC and load.

Remember that DC to DC power supplies are much smaller because existing AC PSU has to deal with the transformer aspect.

I worked for an ISP that was also a CLEC back in late 90s / early 2000s. All of the telco side was DC (massive 48v battery banks) - so when we were doing server implementation it made sense to get all DC PSU on the servers. Not sure why DC PSU aren't a more universal option as you'd think UPS providers could easily offer DC output models.

There are options out there, I ran across this [0] looking for typical ATX DC to DC PSU.

[0] https://lazer3d.com/dc-dc-power-supply-guide/

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

#148

Post by throwaway894345 »

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’d be very curious to understand (even very crudely) the breakdown of those 40W. Roughly how much does each internal component consume at its peak load? Or at least for the top offenders.

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

#149

Post by toast0 »

numpad0 wrote: post #72
jcrawfordor wrote: post #24

Earlier quoted context omitted.

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…

Looks like PoE uses pin 4 and 5 for +48V, and 7 and 8 for GND, which respectively are pair C and D of GbE. On ISDN, pinout could vary but one I could find said 1-2, 4-5 for V+ and 3-6, 7-8 for V-. In either cases, both sides of isolation magnetics are connected to pins of same potential and current is only proportionate to voltage imbalance within each pair which should be minuscule. I wonder if the problem is that 1…

> Looks like PoE uses pin 4 and 5 for +48V, and 7 and 8 for GND, which respectively are pair C and D of GbE.

There's three common pin outs. You've described 'alternate B' -- the unused pairs of 10/100; you can also use 'alternate A', using the pairs used for 10/100. Or 4-pair would have both.

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

#150

Post by erwincoumans »

youngtaff wrote: post #121
erwincoumans wrote: post #13

We powered the Mac Mini M1 using 12V DC, bypassing the built-in AC power adapter, and used it for some quadruped robot experiments. Some details on the connector are here: https://www.ifixit.com/Answers/View/574827/What+PSU+connecto... (that article mentions Mac Mini 2018 but the connector/pinout still works fine for Mac Mini M1)

Ivan also rack mounted a few Mac Minis using a similar approach https://www.instagram.com/p/CvP8FuLtzzr/?img_index=1

That looks cool! Here is our paper with videos of the quadruped robot with Mac Mini M1 on the back, receiving power from the robot https://sites.google.com/view/fast-and-efficient I did a version without enclosure (just 250 gram) and (with DC-to-DC Buck converter for stable 21V -> 12V) but it was too vulnerable, hard to replicate and it didn't fit properly inside the robot.
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