A vampire flash light: the evolution of https://www.thingiverse.com/thing:608693
Simplified wiring. Wiring instructions for battery are provided on pictures.
Other information and instructions are provided through these links https://www.logre.eu/wiki/LOGreLight
EDIT June 2019:
An uptade is added, mainly to integrate metal contacts for the battery. This is version v10d.
The source CAD fmodels are now available in Onshape. Search in Onshape public models "LogreLight_2019". In a first tab, the Flashlight cover, with a configuration selector (choose between one or two colors). In the second tab, the Flashlight case, also with configuration selector (choose between flexible or metal spring).
The casing is also designed to welcome a small PCB which can be prepared (components soldered) before insertion into the light case.