The little lantern mod (part I+part II), finished

I wanted to make a small lantern based on the Utorch UT01, with a campfire/candle colour temperature (2200K). There are not many leds in that colour temperature, I know that the Nichia E21 comes in that tint but Clemence does not have it (yet).

So I came across this über-obscure led at RS-online, the Stanley Electric GSPW1651NSE-20Y-TR :party: . It is a 5050-size japanese mini-COB led with 6 parallel midpower leds in one tiny LES (datasheet). Rated at max 600mA, 85CRI and just 81 lm/W this led will not win any performance contest. But it is 2000K!, that should create some cuddly atmosphere.

I did a quick voltage/output test on one of my 119-boards to see if it would survive the 600-ish mA that the Utorch UT01 provides on an Eneloop.

So the led is ok at least up to 1250mA and should be fine in the Utorch and give a bit under 100 lumen OTF, which is fine for a lantern.

So it was soldered into the UT01 (after the board was sanded down to 13.5mm diameter). To fit the larger than stock led under the reflector the centering piece was left out and the corners of the led filed off a bit with a small diamond file. It all worked and indeed very warm the tint is! :open_mouth: , almost as orange as a PC-amber led, but unlike the amber led there is some of the blue side of the colour spectrum leftover, the tint is just extremely warm.

A peek into the reflector shows the six distinct leds. Of course that affects the beam, a royal donut hole is the result. But it will be a lantern so that is no problem.

I get 88 lumen on the highest setting, and 0.8 lumen on the lowest, a good range for the lantern.

Part II will be the lantern conversion, when I have time to finish it I will post about it.


Part II, the lantern conversion.

This part was intended to look a bit more professional, but the used techniques were a first for me, it was not as easy to get it slick looking.

First I bought a rod of 15mm diameter solid acrylic, that fits almost tight through the bezel of the UT01. A piece of it was cut off, first a 2.5mm hole was drilled in the top, then with a countersink drill a conical hole was drilled. The deepest part of the 2.5mm hole was M3-tapped. A conus was bent from a piece of aluminium foil. And a 16.5mm diameter replacement lens was made from a sheet of acrylic (it looks blue because of the protecting foil).

The plastic on the inside of the conus was liquified partly with a cotton-swab drenched in chloroform, then the aluminium foil was rubbed in place using the swab.

The tail-side of a two-pence coin was filed flat (I would not do that to the queen) and three holes were drilled in it (one through her ear, I reckoned I would get away with that), a hex-screw was used to screw it on top of the optic. The acrylic was sawed to the correct height.

The 16.5mm acrylic lens was glued on the underside of the optic with chloroform, not crystal-clear unfortunately but it will do the job fine. Here it is shown with the bezel already around it.

And here’s the finished light. I painted the coin with matt black heater paint, that did not cover her majesty 100% but it is kind of fun that you can still see that it is a coin.

And the beam is pretty nice, mainly going sideways in all directions. The output is 51 lumen on max, while out of the reflector without the optic on top came 94 lumen. So the optic caused 45% light loss, a manufacturer should be able to improve on that :wink:

I’m happy with the result, as said less perfect looking than intended, but it is a nice little tent lantern that will certainly make me very happy during my camping trips :slight_smile:

Very nice mod djozz. Just need a shot of a bottle of wine with you light shining on it. :slight_smile:

Thanks, right, here’s the proper beamshot:

Very nice!

You’ve got me wanting a very warm Eneloop-powered ‘mood light’ now…

that is stunning! such a warm tint!

Nice! Even though I don’t particularly like very warm tints in real life. :stuck_out_tongue:

Perfect. Now how do I get my darling wife to be romantic? :heart_eyes:

Nice mod :slight_smile: i have a few micro LEDs in that tint range of flame of a candle, but they are to small for in a flashlight host.

Should be cool :+1:

Nice light to get your girl in the mood . Sadly not enough light to find her

I don’t know what’s the better vintage, the wine or the lighting.

really nice tint, perfect for fall and Halloween. I often wonder how creative some users are with sourcing exotic LEDs :slight_smile:
interesting mod and I am looking forward to seeing the lantern.

It looks real warm (was gonna say cool but….)
But I gotta ask, if you want a real warm yellow collor why not go for an amber colored? I’m just curious…

Because of the CRI. Low-pressure sodium gas lamps are way warm but their tint is AWFUL, because they have atrocious CRI.

Yes, I have a flashlight with a PC-amber led in it, which already has a wider spectrum as a normal amber led, but still the blue region is completely absent. This led still has some blue in it so blue colours do appear a bit blue instead of grey.

Nice work Djozz !

About the donut hole , could it be from the wrong focus of the reflector ? I could be totally wrong …

Nice, now you just need to make it flicker and you’ll have a nice campfire

Cuddling afterwards….

As a French person, I’m irritated by that screw-on cap on a bottle of wine… but I DO enjoy the scenery :slight_smile:
Nice lantern ! I love my 219C 2700K for ambient lighting !

Faut bien défendre les traditions, “on a toujours fait comme ça” :partying_face:
30 ans et déjà réac’, ça promet !