I doubt I could draw a completely accurate pipboy from memory but I’m getting there! :D Here are some thoughts about the Pipboy 3000:
The golden rule (as always) is: draw it 200 million times. Don’t be lazy, don’t half-ass it and instead of drawing that cylindrical … weird thing I keep seeing a lot of people draw, put some effort in it every single time. (I know it’s tempting to just… not.) You can use this site to pose a reference for yourself (they got other props and even characters!). If you got the Fallout 4 Pip-Boy Edition, you can just pose the thing irl. As soon as you’ve drawn it a a bunch of times, you’ll start remembering what main shapes it consists of. You don’t have to get the details down right to the last screw. As long as you draw the basic shapes out, everyone will know what it is. It’s really just a bunch of boxes and tubes stacked on/into each other. Geometry studies, yes? ovo