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Kind of misleading. 1) This isn't "PoE" in any sense of being able to power a PoE-compliant device. It's hacking up an Ethernet cable to carry voltage on 2 pa
by brk 13y ago
Kind of misleading.
1) This isn't "PoE" in any sense of being able to power a PoE-compliant device. It's hacking up an Ethernet cable to carry voltage on 2 pairs not used for 10/100 Ethernet.
2) The article recommends a 7805 power regulator if you need to step down 12V to 5V (as in the example). While this would work, 780x regulators essentially throw off the unwanted excess voltage as heat, and total heat output is going to be a factor of the voltage drop and current. 12V-5V for a router (could be 1A or more) could end up being quite a bit of heat. You'll likely need to use an adequate heat sink with it. There are more efficient (and still easy to use) switching regulators available.
- starky 13y agoYou are correct, but you can splice DC power onto one end of an Ethernet cable exactly like this to power PoE devices. It is quite effective, but is more dangerous than using an injector because it will supply power to non-PoE devices.
- chrismsnz 13y agoIt's called "Passive PoE" and some devices support it out-of-the-box (e.g. WRAP board)