8 Port Passive PoE Injector, Managed and Fused

1 Project Scope

My parents' house is widely equipped with Mikrotik routers and other passive PoE powered hardware. So a centralized power distrution seems reasonable. However, passive PoE injectors like the one from Intellinet have one considerable problem:

They use a powerful PSU, capable of delivering a high current to a single port in case of a short circuit on the cable, inevitably causing a fire.

So I wanted to have a PoE injector that has a per-port fuse. I was not ale to find such a device on the market, so I built it myself.

Additional features:

Web Interface
- Current port switching status
- Fuse status
Syslog interface
- Switching events
- Fuse falure events
External powering (24V) from UPS / Battery

2 Component List

SanDisk Micro Secure Digital (Micro SD) Speicherkarte 2 GB: Amazon: 9 €
NEUTRIK Cinch Einbaubuchse, sw, NF2D0: Amazon: 12 €
Neutrik NE8FDP RJ45 Durchgangs-Einbaubuchse, vernickeltes D-Gehäuse: Amazon: 9 €
ah 19" Parts 87407V 19" Leergehäuse 1 HE mit Lüftungsschlitzen: Amazon: 44 €
Ethernet Schild Netzwerk Network Shield W5100 für Arduino UNO R3 Mega 2560: Amazon: 7 €
Arduino Mega 2560 R3 Microcontroller: Amazon: 35 €
Netzdrossel: 5 €
10x Sicherungshalter: 25 €
8x Feinsicherung 500mA: 5 €
Feinsicherung 1A, Feinsicherung 6A, 1 €
Schrumpfschlauch-Set: 15 €
Lochraster-Platinen: 5 €
Stiftleisten, Buchsenleiten: 15 €
8x Injektoren: 30 €
Beleuchteter Hauptschalter: 3 €
Kabelführungen, klebend: 15 €
Kabelbinder: 5 €
Netzteil Meanwell 24V 150W (6,5A) MW LRS-150F-24: 25 €
2x DC-DC-Spannungswandler: 10 €
14 Ringkerne: 15 €
8x bistabile Doppelrelais 5V: 80 €
BME280 Sensor: 15 €
Cinch Stromversorgungskabel: 5 €
Kabelschuhe: 5 €
8x ACS712: 70 €
Gravitech 8 Channel ADC I2C: 20 €
20x R, 50 kOhm, 8x ZenerDiodes 4,5V: 5 €