So I am having a think about a new campaign setting for a campaign and am taking inspiration from a number of sources, wheel of time, horizon forbidden west, see etc. basically post apocalyptic worlds where the “age of technology” was so far ago that while there are still relics the current inhibitors have no idea what they are and they appear magical. 

I also love the idea of my adventurers being able to hunt robot dinosaurs and strip them if parts ;). 

Wondering if anyone has run/played in a setting similar to this, or turned a computer game world into a campaign? 

There are elements of this in the Forgotten Realms. Not just "ancient civilization was more advanced," (which is very common in the Realms), but "technology in the modern sense of the word," (which is less common). The Barrier Peaks adventure, as well as I think the Infernal Machine adventure, allude to such things in 5e. Someone built a robot in Dragon Heist, but it runs on hand-wavey "construct magic" or something.  For older editions there's other stuff here and there. I own a module called Earthshaker, about a giant robot, from AD&D.

It's a tricky thing when it comes to D&D. Your players all know exactly what they'd need to do, to get something working again, or to make use of some old parts or something. Their characters don't. There's a higher than average amount of metagame tension involved. You'll probably have a good idea of whether this would be a problem for your group.

I found a pretty impressive homebrew supplement called Hamund's Harvesting Handbook, which gives you ingredients to grab from every monster in the Monster Manual, as well as drop rates and DCs and so on. It then tells you which ingredients are needed for almost every magic item in the DMG, and a few new ones too. I've yet to play with it, but it might serve you as a starting point for a curated crafting system. You'd likely want to rename a bunch of ingredients and monsters, and no one needs to use *all* the content here, but it probably has what you need. You could replace the minutes-long careful dissection skill checks with something like, "deal at least 5 bludgeoning damage after it uses its flamethrower."

It's a fairly common thing in many JRPGs. The Final Fantasy games were my introduction to the idea.

My current campaign setting fits this, and I'd be lying if I said HZD wasn't part of the inspiration for it. The ancient civilization created the gods of the current day, and there are some twists as to how this came to be and what exactly happened way back then.

Coincidentally, I also introduced a crafting system into this campaign but I discontinued it after the first campaign arc was done. It's a lot of work. A LOT. Not just coming up with a steady stream of dropped components that increase in complexity and power over time, but also generating a list of things that can be crafted out of those components and the recipe for each one. After about 5 levels it just became unmanageable and unfun. And honestly after all that work, the party items that I liked the most and that the party used the most were the ones that were just introduced traditionally rather than crafted.

The pre-made crafting systems I've seen look similarly bloated and tedious to actually put into play. If I ever do something like that again, I'd strip it down quite a bit. Maybe you just have a class of weapons that can accept one component and the different components grant different effects.

Good input!

I think the main benefit to a crafting system (aside from theme) would be that you can provide mechanical rewards for killing monsters that aren't intelligent humanoids. Like, an orc camp could have a magic axe. A cave full of carnivorous penguins, not so much. But if said penguin bones can be turned into something...

Yeah, a simplified X+Y system might be good. Power supply plus effect, maybe. Penguin bots have weak batteries fueled by blood, and a cone of cold blaster that scales via battery power. Rhino bots have a stronger battery that doesn't recharge, and a reactive shield that doesn't scale. Etc.

The Numenera setting might be the type of thing that you're looking for as far as theme goes. To quote the Wikipedia page "Numenera is set on Earth approximately one billion years in the future. The setting is called "The Ninth World" due to the fact that eight civilizations have risen and fallen prior to the current era."

There was some 5e compatible content made by Monte Cook Games for it as well.

I do like the idea of a more wheel of time approach, so this technology seems just as if it is magic, even the magic that can be wielded now is nothing like the wonders of the past. Imagining a character finding a weapon that fires rays of energy (scorching ray spell) but needs time to recharge after use. 

You could abstract the crafting system. Just say, you found 5 crafting ingredients, it takes 10 to make this item, 12 to make that one, etc. Then don’t worry about what the ingredients are, specifically. Seems like that would save a lot of bookkeeping.

Or make some of the crafting ingredients what they need for spell components, so do they make this item, or save the diamond dust for a revivify.