Suggestions on your favorite 5mm LED diodes, preferably with a Vf of ~3V? I’ve been on the hunt for some high CRI diodes for projects, and wanted to pick up some Yujis, only to discover they are completely out of stock and do not plan on making any more going forward.
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Generally THT components are outdated and no longer actively developed, hence why all the new high CRI LEDs are surface mount. It might be cheaper to buy an adapter PCB to run a modern high CRI power LED or even a Sunlike (violet pumped) at the same currents your THT LEDs would’ve run at
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Are we talking “5mm” as in T-1¾ bipin LEDs, or as in 5050 chip LEDs?
Old skool plastic diodes. Those Yuji were “The Thing” back around the time of the Sofirn C01 lights, a couple of people were modding the Fenix E10(?) AAA lights that had cold white 5mm LED.
I’ve found it almost impossible to get high CRI 5mm LEDs for reasonable prices the last few times I’ve looked. I have a few crappy multi 5mm emitter lights hanging around that would be fun (but pretty pointless) to upgrade.
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Pointless, but surprisingly fun. It’s nice to just pop replacements in, and usually doesn’t even require soldering. I just like the idea of a low lumen light, and plan on upgrading a bunch of fauxtons and giving them away.
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Yup this was my original plan, along with one of those “72 LED work lamp” plastic brick shaped things which takes 4AAs, the LEDs are just soldered on a simple PCB so fairly easy to change. Alas, it appears the best LEDs are even less available.
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You could make a small PCB that adapts a Nichia E17 to a THT footprint.
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You could go look on ebay or craigslist etc. for older cheap photography lights, they often had 5mm LEDs inside before they went to SMD.
Found some High CRI LEDs on AliExpress, if you need at least 1000pcs… Hohe CRI 5mm strohhut LEDs Birne LED LIGHTIN diode Warm weiß/weiß LED Lampe 1000 stücke Freies verschiffen - AliExpress 39
Or if you live in 'stralia: HIGH CRI 95 5mm 6-6500K Led Round Clear Top Light Emitting Diode 100pcs Led DIY | eBay
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You’d be surprised to learn how many Photon Freedoms I modded with both the 3200k and 5600k Yujis.
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That’s the plan. I just wanna get a bunch of fauxtons fixed up with better LEDs and fresh batteries and hand them out like candy. Teachers or parents of kids around the school without a light? Here you go. Homeless person around town? Fresh socks, nonperishable food, and a light. Neighbors that can’t seem to see the lock of their front door and are bringing out their phones for illumination? Have a light. They’re cheap enough that I don’t feel bad giving them away, and small enough that most people won’t have any qualms about carrying them.
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I know CookieDave is already aware of the thread, but I felt it is worth adding here to help point others in the same direction - I don’t know if rngwn is still active here, but just in case, check his sales thread for high CRI 5mm LED’s of a couple different CCT’s here:
I have both the 2300K and 3400K, and they are very good. djozz has CRI, duv, and output measurements in the thread showing how similar they are to the Yuji’s, and I have some sustained overdrive testing buried deep in the thread showing they can handle far more power than they are rated for.
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One of the few unfinished 5mm projects I have pending is home brew joule thiefs that fits in common PVC pipe. I have everything collected, including PCBs. It’ll probably be done around the end of the year, work schedule is hectic.
I’m using easily sourced warm white, 50° 5mm LEDs, instead of my rapidly diminishing Yuji stock. The warm white examples I have found really surprised me. Not as nice as the Yuji products, but much better than the usual cold 5mm product. Those Yuji’s make for great swaps in the venerable Photon Freedom and Micros.
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In case anyone was interested, I actually tried to order from that seller a few days ago, but they said I would have to wait 15 days for a new production, as they don’t have any in stock. I haven’t heard back from them whether or not they would actually be making more though.
Found these Hi-Cri 5mm LEDs a good while back on eBay, but don’t like the beam shot photo in the sale. Looks like a dark center in it’s beam profile.
Not affiliated in any way with the seller.
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Hah, I bought the same ones to test with, and while they do indeed have a doughnut in the middle, I’ll take it over the harsh blue/purple that most of these fauxtons always utilize. I’ll probably swap them out with something better when I get a chance, but for the time being, I’m keeping a few swapped with these emitters to give out.
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Oh goodness, I couldn’t tell for certain if it was just the photo. How is the peripheral color ?
I’m probably not the best person to ask about color, since I’m technically color blind, but here’s a quick comparison between the stock emitter and the replacement one from that eBay link. Same distance, so noticeably wider beam.
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That, honestly, doesn’t look too bad , to me. I have a few early Photon Micros that are darn near purple 
I’ve been using these 15° warm whites in the Photon Freedom covert :
And these in the regular Freedoms:
Not HiCri but a big improvement over the stock led.
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Nice project.
You may also be interested in this simple, low power driver design that gchart shared here. Output is determined by one of the resistors used. It’s not remarkable for efficiency, but it can drain cells down to about 0.7V according to this tests:
When time allows, I’d like to try this as a learning project, and maybe see if I can combine it with some other project of interest, like a small thermoelectric generator.
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Most JT circuits will drain a cell down to nothing, but need a certain higher voltage to start.
I had lights that would do similarly: drain a cell forever, but if I’d turn if off, even to “save the battery”, it wouldn’t turn back on again.
Might, eventually, if an alkaleak would build up some resting-voltage after a while, but other times not.
They work great, though, if you make one as a “nightlight” to burn off dead alkaleaks. Wrap in cellophane (ie, line most of the cell-holder) to contain any leakage, then just fire it up at dusk, let it burn its way down overnight.
Oh, and no need for high-falutin’ LEDs in those, as you’re already headed to scotopic vision anyway. WW can be nice and calming, better if 2000K or even 1800K, but you ain’t gonna be distinguishing resistor color-bands in that light, that’s for sure.
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