Poor man's PoE for Raspberry pi-3 under $2

Warning: This blog is about powering your raspberry pi-3 over ethernet cable(length upto 100Meters), It uses Passive PoE mechanism where T568b wire color  Blue/Blue-White is used  for     +(positive) terminal of DC supply Brown-White/Brown is used for -(negetive) terminal of DC supply If you dont know what is a passive PoE, then dont proceed!!!

, instead buy a proper PoE Hat for Raspberry pi-3.

If you are a tinkerer/hw-enthusiest/diy-hobbyist(and you know what you are doing), here is what you need,

1)PoE Injector cable(costs less than 80cents) 2)DC-DC buck converter from aliexpress that costs less than 50cents(Look for Hesai brand). 3)female-to-female jumper wire(cut into 4 pieces) and solder as shown in the picture 4)Cover DC-DC converter in a heatshrink sleev, and connect to raspi-3 as shown. 5)Feed 12v-DC and  Network-connection to the PoE Injector and connect CAT-5 cable(upto 100m) between Injector cable and Raspberry-Pi-3 as shown below

from Hacker News https://ift.tt/2niWrdB