PoE Texas POE-IO-135 | Passive PoE Injector and Splitter Kit with 1.35 mm x 3.5 mm DC Connector and 10/100 Ethernet Via RJ45

Depending on distance (see https://www.poetexas.com/pages/poe-calculator )
the power source could be the power supply that came with the wireless access point, IP video surveillance camera, etc.

This set contains
a very cost effective injector and breakout or splitter component.
The injector inserts the DC voltage at the source location into the 3.5mm x 1.35mm injector plug.
The DC voltage is then carried over the spare pairs of the 10BASE-T or 100BASE-T network cable.
The breakout or splitter extracts the DC voltage from the network cable onto the 3.5mm x 1.35mm splitter jack.

Other Options
Also available is a 2.1mm version WS-POE-IO
Note: if you use this with a 5 volt device - keep in mind that with a 5 watt device, the ethernet cable will lose up to .4 volts every 10 feet - so the distance is limited.
We have a calculator on our web page to figure this for you.
Another method is to use a 6v power supply - this will extend the useful range to about 35 feet - but will cause the voltage at the camera to vary far outside of the stated specs.
Please see our 5 volt active splitters for flawless operation up to 328 feet at https://www.poetexas.com/