This is one of the projects that I use to do this. Without touching anything, it allows you to control the functionality of a 3D printer (or anything that uses G-code). Without touching anything, you can control a machine. Waving your hand in the air, allows you to control a complex machine. That's some Tony Stark future stuff right there. Future stuff in the present moment.
Step 1: Haters gonna hate or why I'm going on a hate rant on the haters
"I dont get it."
"That's... neat... but utterly useless."
"It looks like it makes no difference for a drunk driver who is about to hit you."
"Hmm, I can’t help but think the approach with face detection is a bit over the top."
"This is overly complex."
These are comments I've received from previous projects. It's because of comments like this that I've stalled posting this project for a couple of months. Why? Because I have a feeling that there is a going to be a very vocal group of people who are going to hate it. Yes, I took a very precise machine and made it imprecise and impractical. Yes, gestural control for a 3D printer is not necessary. Yes, there are probably a variety of different things to achieve the same effect.
Why does it matter? It's still an interesting project and it sparks imagination. That is why doing new things, even if they are completely impractical in its current state, is important. By generating new ideas and displaying these ideas, it allows a chance for new ideas to be generated and built from it. I've shown this project to quite a few people and it consistently sparks imagination. The more interesting one I've heard is using it as a computer interface for primate to control a machine to give themselves rewards (like a banana!). That would be fascinating! There have also been a lot of idea for drawing robots, hooking it up to a CNC router to create sculptures, etc. These are the ideas and comments that make it worthwhile! Build on the ideas of others or ignore them, don't try and tear them down by being a sucky, overly critical person. Sucky people suck.