https://www.kickstarter.com/projects/realjds/spartan-hud-nex...
Fun project, made some sales and a small profit, then hand-built and delivered the units from my apartment. Lots of learnings.
Applied to YC and got an interview but ultimately didn't get in - I agree with their feedback that the platform was too general and "lacked a killer app". But it's a cool research platform due to its generality: you get a full Linux computer in your heads-up display, and can connect arbitrary USB peripherals (we had a version with a depth-sensing camera).
Over the last year on weekends I've been working on a new light-weight version that allows one to drop in their smartphone or other ~5" screen, and actually orienting a specific version towards the sport of airsoft. Polycarbonate encasing around a modified helmet protects the electronics as well as the user's head.
Hope to try it out sometime later this year; lately I've been pre-occupied with my day job and learning all the new AI software and theory out there.
If anyone is interested in this project and wants to connect, ask questions, etc, feel free to reach out via email (in my profile). Cheers!