Introduction
I haven’t ordered a LT1 yet and I don’t know if I will ever do. I don’t need a lantern that often. But sometimes… So I thought a diffuser should be enough. You can get simple plastic or silicone diffusers from China cheaply, but I didn’t want to wait and wanted something better. So I created my own diffuser.
Please note that this is not a submission for the Old Lumens BLF Self Built Flashlight Contest because it it not a complete flashlight, just an accessory.
Design
While most simple diffusers are just like a sphere or a cone that diffuses the light in all directions, my idea was to use something similar as the LT1 that does not emit light upwards, but more usable to the sides and downwards. That’s why the LT1 has the LEDs at the top (which adds some complexity and increases manufacturing costs). For my design I wanted something more simple and universal, using an existing flashlight.
So I came up with this design that uses a reflector at the top which reflects the light from below to the diffusing material.
This example (and my prototypes) uses an Emisar D4S (SST-20 4000K) as the base and as the light source.
First (5 minute) prototype
To test the feasibility of this design I made a paper prototype using a throwaway plastic cup (soon extinct in the EU), aluminum foil and some paper (of course!).
Please ignore the purple tint! The camera (app) of my phone has some issues with low light.
Second prototype
So today I bought a small cup of yogurt and a box of something that I probably should not eat all at once O:), because it has a reflective coating on the inside (not perfect, as I will explain later). I won’t go much into the details of the build, but most of it is self explaining.
Cut a circle out of the bottom of the cup so that it fits tightly on the flashlight. Next cut a circle from the box (nom nom) and cut a line from the center to the outside, so that you can roll it into a cone. I used a stapler to connect the overlapping parts, but before you start, test it to find the correct angle! Then cut it to size and use some tape to attach it to the open end of the cup.
And this is the result!
And now with aux LEDs.
I’m rather happy with the results. The plastic cup is too thin and flexible for every-day use. The material that I used for the reflector is slightly translucent, so it does not reflect all light. Also make sure to not use the FET range of the flashlight! This traps heat and will melt!
Future plans
3D printing it? Bayonet attachment for adapters to use it with different flashlights?