Ivan Kuleshov's Modified Apple Mac Mini Pulls Power Over Its Ethernet Port
Jun 14, 2023
Engineer Ivan Kuleshov has made his Apple Mac Mini a little more convenient, by ditching the power supply in favor of Power-over-Ethernet (PoE) capabilities — but while he thinks the project should be replicable by others, he advises against it.
"Keep in mind it’s quite time-consuming. Something can go wrong at every step. You will void the warranty on your Mac mini. So it's your responsibility," Kuleshov explains of his reasoning by advising others to steer clear of walking in his footsteps. "It was an experiment, a test of skills, a topic for discussion, and just a hardware-hacking project."
Starting with a "donor" Apple Mac Mini M1 which was already faulty, Kuleshov first decided to go in blind — just soldering power directly to the network port. "Well, I suspected that it didn’t work that way, and after failure and 20 minutes of reading datasheets and the theory of PoE operation, I laughed at my naivety," Kuleshov confesses. "If you think about it – it shouldn’t work that way. There must be some isolation of electronics. Otherwise, how will a normal network device survive 41.1-57.0V on a network cable?"
The secret sauce, of course, is that Power-over-Ethernet only usually provides power when a device requests it — otherwise it'd destroy any unlucky non-PoE gadget connected to the port. In addition to the hardware required for negotiation, the port needs to include integrated magnetics — which the Mac Mini's Ethernet port does not. To resolve this, Kuleshov upgraded the machine's Ethernet port — including disconnecting it from the motherboard and adding flying wires.
Using this modified port, a transformer, and a suitable PoE module, Kuleshov was able to complete the upgrade — using a diode to prevent connection of a normal power supply from destroying the PoE module and allowing it to be used as a backup supply if required. In testing, the modified Mac Mini could negotiate PoE+ good for 30W — "it's enough," Kuleshov writes. "During the stress test, the highest value was 24.6W (checked in the web UI of the switch)."
The full project write-up is available on the Uptime Lab website.