Here i created fully functional mechanical charger from game Metro 2033 (whole trilogy, to be precise). All parts can be printed on standard 200x200mm printer in ABS or some other plastic (i used ABS). It also need couple of other parts, like bearings, nema17 stepper motor and two shafts 8mm diameter (check pictures for details). I didnt measured voltage output, but i belive its somewhere between 7-12v at the peak. If you are interested into using this energy for powering flashlight or even charging phone, take look at circuit i used for my wind turbine: https://www.thingiverse.com/thing:3138588
Additional parts list:
3x 608zz ball bearings (skater bearings)
1x Pull starter 14mm hex one way bearing, 8mm shaft
NEMA17 stepper motor
M3 screws, various sizes x7
You would also need two shafts which you can make out of 8mm linear rod for 3d printer, by cutting it with dremel or even metal file. They are quite easy to make.
Also, its highly recomended you have super glue and some wire diameter 1-1,7mm for reinforcement of spring and barrel connection.
Bracket connecting generator with mechanism is printed in 2 parts, and later glued, On one part of bracket is included support which you remove after printing.
ALL PARTS ALSO HAVE PADS DESIGNED TO KEEP PRINT IN PLACE IF PRINTED IN ABS. THOOSE SHOULD BE CUTTED AFTER PRINT. they are adding additional ~20min to the whole printing, but will make sure your parts get out nicely out of printer.
I didnt designed place for analog voltmeter as in original model, simply because im leaving to the imagination of people which will print this to figure out how and if will they put it there (and i belive its also unecessary :D)
Charger in action:
DISCLAIMER: this is surely not most efficient way of producing electric energy, as you will see, but its surely very cool. I didnt modeled this to be original as in game, but ive had to adjust couple of parts to be 3d printable. Im not claiming owner of Metro2033, Metro Last Light or Metro Exodus brands. All logos, names etc are belonging to their rightful owners. This charger is nothing but mechanical assembly inspired by models from game.
Parts are all printed flat, no support, no rafts. If they have pads, print them flat down, and cut them after printing. They will prevent wrapping of parts if you use ABS plastic. In spring+barrel part, insert metal wire and glue it there into 3 holes, as reinforcement, because i belive its weak point. Use thin metal cable or strong rope to connect barrel to the main handle. If you have any questions, feel free to ask :)