The 4th Annual BLF / O-L Contest; MtnDon's Entry, Hand Made Class

Never seen anything like this. Question - could you use any led that has had the phosphor stripped off? For example, I know I am not the only one who has stripped an mt-g2 trying to dedome it. Could an mt-g2 give more efficiency at these lower power levels?

One would think that any LED without the phosphor layer should work. I am no expert… am just beginning to dabble in this remote phosphor / royal blue wavelength thing. The claim is that an emitter such as the XT-E royal blue, is more efficient with a remote phosphor than the same emitter with the phosphor attached. Cree and Intematix have assorted literature if you search online.

FWIW, I have also seen quad emitter versions much like an XPH35/XPH50 in choices of 6 and 12 volts. And just now I did an ebay search and found a 3 volt quad version here.

It’s a neat idea for ambient lighting but counter to the point source we need for a focused beam. This contest is a great place to explore such notions as it probably gets wider notice and there isn’t a presumption of throw.

Well, I stole a couple of hours from home improvements this afternoon. :open_mouth:

Has anyone wondered how this led and remote phosphor was to be utilized in my lantern light? Here’s what I have been thinking of.

That is a mug that has a Ball Jar type threaded top. Sixteen ounce size. have a pint, eh! I found it online at “discountmugs” They sell promo items with company logos. They also sell samples with no logos. It comes without a lid so now my wife’s pantry is short one lid and ring.

The plan is to mount the heatsink on the top of the lid…

Heatsink, lid and LED sandwich…

Plan A would be to mount the phosphor dome right over the LED / MCPCB…

That places the dome up and behind the metal screw on lid band. I’m not sure if that would cut light output or not. Plan B is to make a spacer to move the dome down. So the making of a prototype spacer is featured next. (that will post shortly in the next message)

After I have the spacer done, when it is dark tonight, I can compare Plan A to Plan B. Unfortunately it will have to be a visual estimation comparison as I have no lux meter

Hi MtnDon,

Nice concept.

Photo’s not showing as of Sunday Night GMT +1 (England).

Cheers,

Splott-Light :slight_smile:

I’ll have a mug of your finest hi cri please to go with my BLF.

Prototype spacer. I also have other reasons for using a spacer. I’ll get into that later after I see if there is any light output penalty…

First step is to use the drill press to hole saw a blank…

The first blank was done with a 2-1/4” saw and was too small. This one with the 2-1/2” was a tad too large to fit inside the neck…

The drill press was used again along with a rasp and then sandpaper…

That did work although the blank turned out slightly out of round. End grain and side grain of the wood removed at different rates I guess. Then I sawed out the center…

We have a donut!!

I used 80 grit paper on the benchtop to hand sand down the high spots…

To locate the position of the heat sink mount holes I made a pencil tracing. Yes, I am a mystery / detective fan!! :wink:

The punch marked the holes…

With the holes drilled through the lid, the LED was trial fitted with the heatsink on the top side of the lid. The spacer was temporarily fixed in place with double stick tape…

Like so…

Some temporary power hookup and we have light!!!

Now to wait for nightfall to see if the spacer causes any appreciable reduction in light output. Don’t know if many photons will get absorbed by the wood. Maybe line the spacer with aluminium foil?? (I never should have put the window in the workshop / garage….)

I had a moment of brain fade and forgot how to post images here. :person_facepalming:

Cool, you can pick up some efficiency by sticking a reflector in the donut. Anything that fits will recover energy lost into the wood. I think your right about end/side grain. To stay round the wood can’t wobble and the cutting surface(rasp, sandpaper, whatever) has to be fixed. At least that’s been my experience. Threads also seem to grab unevenly in the chuck so I use a carriage bolt with the end removed. Sometimes I’ll press a bushing into the table but that can be a false security and may or may not put more pressure on the chuck.

If I have time tonight I’ll try it in the darkened shop with
(a.) the spacer as is now
(b.) the spacer with an OP reflector from an S2… it fits the hole and thickness of the board used
(c.) no spacer, dome right over the led.

I dug out my old Sekonic L28C2 photo light meter… really old school thing. (That dates me I think… :laughing: ) A selenium cell and analog meter. I have no idea if it will be able to discern differences at the light levels I intend.

Wow! I do wish I had a modern digital lux meter. I think that will be the next thing I buy. I’ll have to do a search on the topic of what’s good.

My old Sekonic analog meter showed the best output to be without any spacer and the dome placed directly over the emitter/mcpcb, listed above as setup (c.).

With setup (a.), the spacer in place but no reflector, the output was noticeably lower. In photographic terms there was slightly more than 1.5 f-stops less light, measured at the same point and distance from the dome.

With setup (b.), the Convoy S2 reflector inserted in the spacer center hole, the output was almost as good as with no spacer at all. Maybe only 1/4 f-stop less than no spacer at all, setup (c.). Considering that I have other reasons for the use of a spacer I believe this is the direction I will take. I used a small plastic “washer” under the reflector to insulate the reflector from the mcpcb.

I may do some further tests with a different reflector I have from an old mini-maglite and with changing the height of the reflector or perhaps the spacer thickness. But that will have to wait a bit.

Thanks to RFD for affirming that photons may be getting lost due to the wood spacer.

Interesting project. Remote Phosphor was a new one on me. Always good to learn something new.

No spacer should be the brightest. Next the spacer with a reflector in it. The wood will definitely absorb light.

Some more prototyping…

First, for those who don’t know and want to know, a forstner bit is made to drill a flat bottom hle in wood. This is one…

I need a cell holder. Here’s my first idea/attempt. The layout on a glued up piece of pine. This is a first prototype. I intend to use hardwood for the final.

Here it is drilled and cut to rough size. Drilled with drill press and corners cut using a cut off / mitre saw

I neglected to take in between shots for this prototype. For the final I will remember! I used a coarse hand rasp, then a finer one. The final version will be taller or perhaps an upper and a lower disc with dowel or tubing separators.

The block and cells do fit through the neck of the mug…

… more later…

Now thats different. I’ll be sure to check the bottom of my cup when I drop in for a drink. :+1:

Cool! It seems likely you could fit a fifth cell in unless you’re planning a 2S2P arrangement.

Not quite enough space for a centered fifth with the size restraints caused by the mug neck inside diameter. There’d be no wood left to hold things together.

Love the design, way outside the box! BTW, what is that little power supply?

Found it on ebay a while back. Search for “Mini Programmable Adjustable Digital Regulated Power Supply ” or something like that. For my flashlight needs I power it with a 30 year old TripLite 12 volt 10 amp benchtop power supply. The “MPADRPS” can put out amps but needs some fan cooling to sustain that. ….another little project that needs doing…. There may be better ones, but I only paid $20 probably a year ago.

Did some more today. I forgot myself and had glued up and begun to cut the cell block and missed taking some photos. :frowning: The block I believe I’ll be using started out glued up like this one. Except the one I used is maple, padauk and walnut, whereas the light colored wood here is red oak. The orange wood grows like that. It is african. Walnut is from a friend’s farm in VA and the maple is a left over from a 25 year old table project. never throw much out.

This is the one I am using. I cut the pieces mainly using the mitre saw. First I cut it to a square, more or less, then an octogon as shown. I end up with lots of cool little shapes of the different woods.

Then it was to a vice.

I began rounding off the sharp corners with a coarse wood rasp.

After a while it was somewhat more cylindrical

Next a switch to a finer toothed rasp/wood file

Much better, but only close…

Yes, that is me hand filing and using the camera self timer

Once the shape was close to what I wanted i also filed lengthwise to try and get the best cylindrical shape

This is a better fit than the first pine prototype.