Powering a LED strip
Powering individually adressable strips is tricky. If you planning to use it with full brightness, keep in mind the conductors on strip can not hold big current, so you need to run some wires in parallel with strip and connect it to strip in middle. Depends on brightness you are setting. Minimal consumption of one chip is approximately 1mA. Power distribution need some planning. Controller consume small amount of power and provide only data signal. Just common ground and logical level should be proper, according to LED chips datasheet.