I've been thinking about this project for a long time. Many years ago (mid to late nineties) I took a lot art classes just for fun. I explored a lot of media including drawing, ceramics, photography (we used a thing called "film" back then), but my favorite was jewelry. I did mostly fabrication, and specialized in lockets and other enclosures. One enclosure I've always been fascinated by is the reliquary. I'm not sure of the Webster's definition, but I see them as a small secure places to keep something ancient and treasured. Now, one of the things I've always held with that group of ancient and treasured objects are stones containing carved petroglyphs. I'm thinking a stone bearing a personal totem encased in a wearable reliquary would be a brilliant piece of jewelry.
Jump forward to today, or at least the recent past, when I finish putting my ShapeOko together, and the first thing that occurs to me is "I wonder if I can get it to carve petroglyphs?". Today's project is the beginning of that exploration. I don't want the glyphs to look machined, so I'm attempting to build a vibratory hammer type thing. This version is a simple electromagnet with a hardened steel plunger retracted with a rubber band. After playing with this today, I'm not sure I can get this design to go fast enough. I might need to go to active position control of the plunger. Right now the control circuit is a 555 driving a TIP120 - pretty simple.