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DIY PoE Injector: Powering Your Devices on a Budget

 


DIY PoE Injector: Powering Your Devices on a Budget

DIY PoE Injector: Powering Your Devices on a Budget


WARNING : Proceed with Caution

Power over Ethernet (PoE) technology is a convenient way to deliver both data and power to devices using a single Ethernet cable. However, purchasing a pre-made PoE injector can add extra cost to your project. This guide explores building a basic DIY PoE injector, but be warned: Working with electronics requires caution and electrical knowledge. If you're uncomfortable with electronics, it's safer and potentially cheaper to purchase a pre-made injector. This only works for devices which need less than 100MB of speed since we are going to remove 4 wires to send power which converts our 1 or 10Gb cable into !00Mb. This is sufficient for cameras which only need like 5mb/s or for Wireless access pints up to 100 mb/s (your internet speed not routers maximum speed).


Safety First:

  • Always double-check your connections before applying power.
  • Use appropriate tools and soldering techniques to avoid damaging components.
  • Ensure your power supply matches the voltage and current requirements of your device.
  • Not all PoE devices are compatible with DIY injectors. Research your device's specifications before proceeding.


Materials:

  • Ethernet cable (Cat5e or Cat6 recommended)
  • DC power supply (voltage and current matching your device's needs)
  • DC power jack (to connect the power supply), it can be either drum connector or JST connector
  • RJ45 jack (to connect the Ethernet cable)
  • Resistor (optional, value depends on PoE standard)
  • Diodes (optional, for enhanced protection)
  • Soldering iron and solder
  • Wire strippers
  • Enclosure (optional, for housing the injector)



Steps-By-Step Tutorial:

  • Prepare the Ethernet Cable: Choose a suitable length of Ethernet cable.  About 4 inches from one end, carefully strip the outer jacket to expose the inner wires. Untwist the four colored pairs and identify the wires you'll be using.
  • Now we need to isolate the the blue & striped blue and brown & striped brown pairs from the RJ45 connector.
  • Remove about a inch worth of insulation from the wire from each side and cut the wires from the routers side (blue and brown pairs). Make sure the wires are isolated and power does not flow to the router or switch.
  • now strip all 4 wires and connect the blue pairs to gather, this will be out +ve (positive)wires and and then the Brown pairs to gather which will be our -ve (Negative)

  • Power (+): Connect the positive wire from the DC power supply (usually red) to the blue wire pair we just made (Blue + White with Blue Stripe)
  • Power (-): Connect the negative wire from the DC power supply (usually black) to the brown wire pair (Brown + White with Brown Stripes)
  • Data (optional resistor): In some cases, a resistor might be needed between certain data wires (consult the PoE standard for specific values). Usually this is not required but some sensitive equipment's may need it. Cameras usually don't requires these.
  • Soldering Connections:  Solder the power supply wires to the designated Ethernet cable wires. If using a resistor or diodes for additional protection, solder them into the circuit according to the chosen PoE standard and any additional safety measures you may want to implement.
  • Use tape to secure the loose ends. Make sure the router side is isolated from the DC wires.


Testing and Usage:

  • Double-check all connections.
  • Do not connect the injector to your device yet.
  • Use a multimeter to verify voltage is present on the blue and brown wires of the RJ45 jack (ensure it matches your device's requirements).
  • Once confident about the connections and voltage, you can connect the PoE injector to your device using the modified Ethernet cable. Remember, this is a basic DIY solution and may not offer all the safety features or advanced functionalities of a pre-made PoE injector.


Alternatives and Considerations:

  • Pre-made PoE injectors are readily available and often more cost-effective than building your own, especially if you factor in safety components and potential rework.
  • Consider the warranty implications. Opening a device or modifying cables might void warranties.
  • If you're not comfortable with electronics, seek help from someone with experience or opt for a pre-made injector.


Conclusion:

Building a DIY PoE injector can be a rewarding project for those comfortable with electronics. However, prioritize safety and ensure you understand the potential risks and limitations.  For most users, a pre-made injector might be a safer and more reliable option.