[MrForbes]

McM sells parts mostly for industrial applications...so yeah, they'd say you need to use a power supply to get DC, assuming you're powering it from awall outlet. Since you're building a robot that runs on DC, you need to get DC from your robot power system, and a Spike seems to me the obvious way to do it. You could even use it to reverse the current to release the magnet (as the description on the McM page about power supplies implies you must).

I haven't used them, but please let us know how it works out!