In case you're wondering, that "amulet" is powered pretty much the same way as the time machine.
TRANSCRIPTION COURTESY OF JOSEPH HOUK - [495; BG is showing Merlin how to use the amulet "toy" from 2067] (BG) "…And all you gotta do is say, 'Abracadabra', plus any item in that list, and it'll shoot out! Try it!" (Merlin, looking down at the amulet) "Abracadabra, Giant Cobra! [A huge Cobra rises into the air with a HISSSSS] ASTONISHING!" (MG) "I've now got it calibrated to respond to only your voice, and if the amulet starts to say 'low power', all you have ot do is set it in direct sunlight for a few minutes!" (Merlin, confused) "Low… power?" (BG) "Oh yeah… Y'all don't know about electricity or batteries yet…" (Off-screen voice) "It came from BEHIND THAT HILL!" (MG) "Oh crap, we've attracted some attention already!" (BG, looking on at the group of men – dare we say, knights? – arriving on the scene on horseback) "And from the looks of it, they're not just any type of startled wanderers!" (Rider, who looks rather kingly as he approaches) "WHO GOES THERE, THAT CAN SUMMON BRIGHT VISIONS OF DEMONIC SERPENTS?"