My version of a needle based foam cutter

Some time ago, I came across this forum thread about cutting foam with a reciprocating needle.  There’s also a pretty good summary that distills a bunch of the details.

Here’s a video that talks about my experiences in getting such a thing to work:

 

Here’s a link that I mentioned in the video about working with the HC-05 module

The other stuff is all pretty easy to find with some simple searches.