These are designs I made for my new tutorials, the Tech Tips Series: Intermediate! Lessons 1 & 2 are finally out. You can find them on my gumroad page, or here on artstation. 
These tutorials are aimed at designing hard-surface and tech-oriented concepts. I don't go into a lot of technical detail, but more so discuss the Check it out if you're interested!
https://gumroad.com/l/fHKw