DC 21-36V 1500mA Constant Current Driver LED Power Supply 5mm Yellow LED(300-400mcd) (Pack of 1000) TTP223 Input Voltage 2-5V Maximum

TTP223 Input Voltage 2-5V Maximum Response Time 60mS in fast mode

the quiescent current is nearly constant

The output voltage changes by 10mV for every °C change in ambient temperature

The 2-Pin Female Pluggable Terminal is a Right Angle Terminal  pitch 5

There are already many projects in the open-hardware community that use the RC522 - RFID Communication with the Arduino

DC 21-36V 1500mA Constant Current Driver LED Power Supply 5mm Yellow LED(300-400mcd) (Pack of 1000) TTP223 Input Voltage 2-5V MaximumLED Drivers serve as an interface between the power supply (line) and the LED (load), converting incoming 50 Hz or 60 Hz AC line power at voltages between 85 to 265 Volts to the regulated DC output current. . Within a set design range, an LED driver circuit should be immune to voltage spikes and other AC line noise. It can filter out harmonics in the output current to keep them from impairing the LED light source's output quality. IP67 Waterproof LED