All the best Asian8640. Good to see you here. 
Nice to see your entry. Wish you fun with your build. 
Welp. You caught me. I’m either using the 3400k or 2300k from rngwn. I purchased a 50 pack of each. It was too good an offer to refuse. Thanks for the tables by the way! They’re sure to be useful. My old reliable regulated HP bench supply bought the farm and I’m going to need it repaired, so there was no way I’d be able to get those number on my own for now.
Thanks for the warm welcome. It’s daunting coming from you though 
1. Try to simplify your circuit as much as possible. Just include a 1,2V source.
2. Putting 3 cells in parallel isn’t good for balancing, unlike with lithium-ion cells.
I mean, I’ve run NiMH in parallel before just fine. In parallel, the voltage will be the same 1.2V with just a larger capacity. The only thing you don’t want to do is charge NiMH in parallel due to the way voltage peak detection on NiMH chargers work. Charging in parallel is a good way to kill a whole bunch of cells at once, but I’ve never heard of draining them in parallel being an issue.
Part 2: Driver “Prototyping” (12/21/2019)
Sorry chaps! I haven’t had that much time on my hands as I’ve been waiting for parts.
I’ve come to the decision that since my circuit outlined above was basically a slight modification of a manufacturer’s recommended setup for their 2218 3v voltage regulator chip, I’d just buy one of those tiny factory implemented 3v boost circuits and go from there, as buying the parts to make the boost section would have cost me $25+shipping with a ton of capacitors and resistors left over since you can’t really buy what you need in small quantities, and if you did, shipping wouldn’t really be worth it. All I needed to do now was throw a resistor on the end of the circuit to regulate the current as voltage would be constant until battery voltage dropped too low. Also, this factory implementation is fairly efficient, so I wouldn’t have to go mucking around improving efficiency. I intended this light to be relatively practical, not just an exercise in manufacturing via blood (I’m clumsy).
Here’s my trusty old bread board testing out a 5v boost driver and 100 ohm resistor on one of rngwn’s 2300k 5mm LED’s This limits the current to 21.9 mA +/- 0.1mA with the resistor dissipating 38 mW.
You might be wondering why the hell I’m using a 5V boost circuit after saying I was going to use 3V? Wouldn’t that mess with my efficiency? Answer: Yes, it would definitely decrease efficiency as the resistor would need to dissipate more energy. However, when my LED’s arrived, I didn’t yet have a 3V boost driver, and as of this point, still do not although a pack of 8 is on the way. I still wanted to test the LED’s and didn’t have anything else. After trying both the 3400k and 2300k 95+ CRI LED’s, I found the 3400k to be too cool a color temperature for the lantern’s intended use and settled on the beautiful 2300k. Honestly, I might just buy a huge pack from rngwn because I love these little warm LED’s so much. I need to get more so that I’ll never run out and stuff them into everything. :D.
Part 3.1: Wood Selection and Layering
Tools to be used
Work area
After mulling over it for a bit, I decided to settle on poplar for my wood of choice for this build. If you’re wondering if that is a bit at odds with my intent to use a darker wood, you’d be correct. There were a few things that factored into this choice.
- If I wanted the wood to be darker, I could just stain it before finishing
- I’m particularly cheap and this 3.5” x 48” x 0.25” piece only cost me $3 from the local Home Depot.
- Poplar is in that happy medium between hardwoods and softwoods. Although it is classified as a hard wood, it is much easier to work with than say something like Maple. As a hardwood, it has a very fine grain which would make for a nice smooth finish.
I took the board and cut six pieces of 3.5” x 1.5” x 0.25” to glue together in order to make a layered stock. Titebond Original Wood Glue was used as it is one of my two personal preference for wood glues, the other one being Elmer’s wood glue which I didn’t have on hand at the time.
Clamped together using 1.5” Hazard Fraught (Harbor Freight) plastic clamps.
It was as even as I could get it, but it looked like it could use quite a bit of sanding
Here we go with the sanding. 80 Grit 3M Sandblaster Pro! That sandpaper is great. It’s well worth the extra buck or two for a much better sanding experience compared to every other sandpaper I’ve ever used.
… Three Hours Later
Time to square off those ends with a Stanley saw and a cutting jig. You’ll also see the diffuser I intend to use, although in its base state. It’s a high quality Carlisle 1.5 oz. plastic shot glass that I’m going to chemically “frost” with paint thinner. Cheap and durable, though I had to buy it it in a pack of 24. Good thing I don’t intend for this lantern to be a one-off.
That’s all for now folks! I intend to round out the square body and make the fittings to hold the light diffuser/shot glass to the body. Also, a flared base might be in order! It might be a while before I find more time to work on this, but I promise I’ll update as soon as the next phase is complete.
I know that one
Good to see you making progress :+1:
The plan is taking shape. 
Welcome to the challenge Asian8640 :) I’m liking the look of this “Dark Stained Wood, Brass, Copper, Dark Red”
Good luck, mate
I am eager to see what's next low lumen mate ! 
It is good to see the progress you are making.
I still have a pile of parts and an idea.
Looks like you have a good start Asian8640! I like your design of a “high CRI with the lowest color temperature possible to mimic low power incandescent.” Looking forward to seeing it all come together.
Part 3.2 Stock Removal
It’s time to remove the stock for a nice round base!
Wait a second….
- None of my drill bits are long enough to drill all the way through the stock.
- My chisels are rusted and chipped.
- I don’t have a working drill press.
- I can’t drill straight with a hand drill.
CRAP…. I didn’t think this far ahead.
Not to mention I can’t saw straight down over long distances very well with the tools and skills I have.
This step is a FAILURE
BACK TO THE DRAWING BOARD!
Part 3.3 Lantern Battery Compartment 2nd Try
Let’s build this one from the ground up using the same construction methods, but in parts.
Note: Length width and height are with the chamber on its side as that is how I am building it.
First, the base and cover for the AA Battery. It should have been a 55.4mm length x 14.6mm width x 14.6mm height chamber but I decided to give myself a little wiggle room. It ended up being within .1mm of 15.5 for both width and height as far as chamber width is concerned.
Then the top and the bottom. Top: 15.5mm length x 15.5mm width x 16.1 mm height. The bottom 18mm length x 15.5mm width x 16.1 mm height
Those parts are finished!
Time to make the sides in the same manner. 88.9mm length x 12.7mm width x 40mm height.
A little clamping
A little sanding
A little test fitting
And a little gluing
Part 3.21 Interlude: Paint test, light diffuser frosting preview, and potential dimensions for the top of the lantern.
I decided that staining the wood might not be the best idea in winter weather. I don’t have an area that is both dry, warm, and contains sufficient ventilation (no fume hood anymore) As such, I decided acrylic paint with clear lacquer over it might be a better fit. Here is a test piece using left-over wood. The center is FolkArt Imperial Red, the right is FolkArt Real Brown, and the left is Nicole’s Craft Studio Dark Chocolate. I’ve already decided to use Imperial red due to how saturated it is, but I’m leaning toward the Real brown versus the Dark Chocolate. What do you think?
I got a little lazy and forgot to document the process of testing out different ways to get even diffusion. While I do have each of the failed finished products, I don’t have as many photos of the in-between steps. Here’s a preview of one I tried with varying grits of sandpaper from R80 to R600 grit sandpaper.
EDIT: UNCLE SAYS ONE MORE THING! I might not be able to implement copper in this build. I think I’m going to stick to brass as most of the washers, screws, and nuts I have purchased are brass.
Nice comeback Asian8640. Its coming along nicely.
Hey mate! Thanks for the visit! However, this isn’t your 5mm LED sale thread. It’s my BLF contest thread. I’m honored that you’re following it, but you probably should re-post in your sale thread.
Looks like you’re making good progress!
One thought if you still want to have variable output is to use a potentiometer (perhaps one with an off position) to vary your resistance. Cheap and simple.
Thanks for the thought! However there were a few reasons I ruled out a potentiometer. The first would be repeatability of run times. All I want is 2 modes, low and high with predictable battery life. Second, audio taper pots, which is what I need as the way we interpret magnitudes of light and the loudness of sound are both logarithmic functions, may not always be available in a replacement size. Mechanical switches will be around in their current form for a very long time.
Nice progress Asian8640