Thinking again, I guess I could use the board in the O.P. sort of like a "driver board" and just wire a standard XM-L on a star from that board. That would work, right? It could be perfect if that center pad is where my B+ contact could be made. Anyone know if that's B+ at the center?
-Garry
that’s a pretty good idea - you could epoxy or screw the two together, bottom to bottom.
i bet w/ a 20mm copper sinkpad plus that, you’d be ok w/ 1W, if you don’t mind a little heat sag
I would guess, that you can glue an XML with removed contacts, on the middle plate. Then wire them from the top like the direct on copper style…
No, center pad should be electrically neutral, at least in stock form. Look close and you can see the traces. If the center pad is also isolated from the backing, you could easily make it the B+ with a jumper wire.
True! Good idea.
-Garry
garrybunk,
Just noticed your address, small world, I work in Johnstown.
Hey Garry, you could take an XML star and glue a 7135 to it, wire B+ to led+ and Vdd pin, led- to 7135 output, and 7135 gnd to B-. It’ll work anywhere, in just about any host. There just isn’t that much heat generated at .35A.
I was waiting for the "duck" to chime in! Thought about your solitaire mod with the 7135s. I guess that's an idea, but I'm liking the idea of these two boards with something like a thick washer between them.
-Garry
Welcome to BLF! Yes, small world! I take it you've been a lurker to the forum?
-Garry
Yeah, there’s a lot of great info here, I used to get the majority of my flashlight fix at CPF, but that seems to be changing. Thanks for the welcome.
I was thinking about something like this for a light for each of my daughters, but I thought that you needed that reverse polarity diode there to also drop some voltage to the Vdd pin (as well as provide reverse polarity protection) - not the case I guess? It would certainly make things even simpler. Plan was to mod a couple of ancient 3xAA 5mm LED lights I got for a wedding present 10 years ago.
If you need the center positive contact you could use a single mode board with only 1 chip and wire that to your XML board with 2-3mm of washer in between. It will have the diode still. I have some blank boards if you want a few loaded with a single chip let me know and I can pop them to you.
I just slapped something together similar to the OP image. Sorry, I didn’t have a populated 20mm star. I left out the reverse battery protection. That would be a diode between the star + and the 7135 Vcc pin.
Edit: I forgot to add, the negative wire goes right on the 7135 tab. It’s a little hard to see in the shot.
Edit2: I just realized, you might not want to use a contact board. My hack was for wiring to something else. You would need something more than what I pictured below, to handle the positive cell contact. Negative is a little easier if you use the wire to ground to the star or the host somewhere.
I'll admit I haven't read the whole thread, but here a picture I saved a while back is.
Relic, this is brilliant. . But. Probably would interfere with the optic.
Now, the op. Star question. . Get some copper flashing off eBay, cut two small stripes, solder positive an negative to LED, apply thermal epoxy to copper strips near center. Solder your led contacts to plus minus, solder neutral center without contact of led plus minus. . I have to try.
Yeah, takes those “bead” type LEDs. Colors, UV, white… if a craptastic LED is good enough, these are perfect.
Can drop on a 2nd 7135 for 700mA, too.
Work great for simple 2-wire hookups for shelf-lighting, cabinets, toys, etc. How else to get an emitter, current reg, and RVP, all on one easily-mounted star?
I kept expecting to see these with a cree footprint but it never happened.
Wow, another thread revival. Much more interesting than all these group buys lately. Now if Garry could post a picture of those famous red rags of his! 
