Here I made 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 measure voltage output, but I believe it's 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 the 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, it's 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. THOSE SHOULD BE CUT AFTER PRINT. they are adding additional ~20min to the whole printing, but will make sure your parts get out nicely out of printer.

I didn't design a place for analogue voltmeter as in original model, simply because I am leaving it to people's imagination who will print this to figure out how, and if will they put it there (and I believe it is also unecessary :D)

Charger in action:

https://www.youtube.com/watch?v=8zk7IVHSvHQ

Mechanism principle:

https://www.youtube.com/watch?v=lKog973s8js

DISCLAIMER: this is certainly not the most efficient way of producing electric energy as you can see, but it is surely very cool. I didn't model this to be original as in game, but I had to adjust couple of parts to be 3D printable. I'm not claiming ownership 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.