I need someone to explain this to me.

Low voltage coil gun

[Andrew] sent in his low voltage coil gun. He used some control hardware that most hardware hackers probably don’t have on their shelf, bit it’s still a good proof of concept. Each coil is driven by a dedicated relay, and a PC power supply feeds the system juice, while a programmable logic controller does the work. Since it’s just a matter of triggering the coils in order, the PLC could be easily replaced by a micro controller.