12A 7135 Based SRK Replacement Driver

Flashlight Modding and DIY Parts
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If you’re sticking paper to sheetrock with a hard drive magnet, you’re probably using much smaller magnets than I had in mind. Older, larger hard drives had bigger, stronger magnets which would easily pull the nails out of sheetrock. Many of them are strong enough that they can never be allowed to touch their paired magnet or directly come into contact with ferrous metal, because the attraction is strong enough to break the material the magnet is made of.

With those though, we’re still in the realm of relatively safe magnets… as opposed to the really crazy ones which can’t be in the same room as anything reactive. Those are the ones which are so hard to transport.

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Never seen a magnet that could pull one.

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… and I’ve been harvesting magnets from hard drives since before PCs were made. Up until last week.

No brag, just memories.

Lots of broken pieces, uncountable blood blisters from getting “skin in the game”. Definitely amazing attractive power, but not magic. Put a few on the inside of your toolbox lid for keeping wee screws from disappearing, as well as wee wrenches. Neodymium can hold screws through toolbox metal.

Keep a tiny chunk of broken Neodymium in a void in my Leatherman, to prevent dropping small parts. Works great!

Fasten your soldering iron’s wire holder to something, then stick a HDD magnet on it to keep your iron from falling. Saves blisters & holes in carpet if you’re clumsy as I am.

Made electromagnets with nails & wire & car batteries before I was old enough to drive. Great fun there! Nails disappear at great speed if you wrap a drinking straw with speaker wire, insert a nail & touch a car battery…

My BF growing up got an Erector Set, to which I added an electromagnet like in junk yards. Dumb idea. Even with a 6v lantern battery for power, Erector Sets draw electromagnets more than the toy cars do!! And the edges of erector set beams don’t give blood blisters, they give deep, gushing gashes!

Even built the “anti-gravity” magnet setup, but gave up trying to generate enough DC voltage to get it to move.

A friend uses Eddy Currents to test metals in nuclear power plants. That’s interesting magnetism there!

Worked last Monday on an MRI system. Not with the magnet, but the computer interface.

Love to see the big stuff. Love to learn more about magnetism!

Maybe the nails pulled from sheetrock missed studs…?

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Sounds like a lot of fun. :slight_smile: I’ve only done a little experimentation with magnetic propulsion, er, rail guns… enough to enjoy the concept but not enough to make anything useful. Just enough to make some holes in the ceiling. Oops.

I suspect the nails I pulled weren’t in studs, or at least weren’t in very deep. I was using relatively weak magnets though, since I’ve stayed away from the ones which are several inches thick.

In daily life, I mostly just use magnets to attach things to the iron frame of my desk. I also keep a little 9.5mm x 2.5mm neodymium magnet stuck to my purse for the random occasions when I need one.

I still have a big jar of iron filings I extracted from sand as a kid. It’s fun to get that out once in a while to show to people who have never played with magnets. (which reminds me… I should do that again soon)

BTW, if you want to see a cool trick with magnets, look up quantum locking or quantum levitation. There’s a fun TED talk about it.

…

I just remembered this thread had a topic. What was that again? :slight_smile:

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Thread topic? :smiley: Ha! This is BLF remember.
In fact I find the best threads are the ones that go the furthest off topic.

Quantum Locking TED talk Boaz Almog: The levitating superconductor

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OH! OH!! OH!!!

Get a powerful magnifier and check those “filings”!!!

You may find them to be, actually, ’’ micrometeorites ’‘, aka ’’ Black Sand ’’ which is the bane of gold prospectors! Scroll down to Part 4 for the Black Sand stuff.

Dittos to Helios- on the interesting stuff BLF threads lead to! Someday, some “information miner” will have a field day panning for the gold buried in the later posts in some of these threads.

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Interesting, since “black sand” has meant Titanium as it’s found in the sands in some 90% of the Earths crust…non magnetic too of course.

Good stuff here! I use a magnet from a hard drive in the lid of my tool box, been there for nearly 20 years. I also have one on the side of a locker with a copper wire attached, holds my wife’s sunglasses right where she wants em. :slight_smile: Inside the locker door, another holds the scissors ready for action. And another affixed to the fluorescent desk lamp gives a finger grip to move the light into position easier.

Dad used to use one to attach a bicycle orange flag to his trailer tongue, made it easy to see just where the tongue was for backing in and hooking up. Now he uses a back-up camera as he traded off the fifth-wheel trailer for a bumper mount version.

My 6 yr old plays with magnets almost daily. :slight_smile: And lights. He has 7 lights, a whole slew of magnets. (not hard drive magnets, don’t worry)

A good hard drive magnet, screwed to the underside of the desk, makes for an instant pistol holster… (glue velvet or felt over the area for a soft attach/breakaway that won’t scratch the gun)

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waiting for USPS as I type this. I will test with 4 – XM-L2 as built. I have run all paralleled on 10 amp bench @ 4.2 supply for up to 1 minute (Turbo!) before shutting down due to heat. Thinking of sectioning off into two zones down the road.

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I got one of the BLF SRK drivers in the mail today from RMM. I’m really excited to get it into my SRK and test it. It’s a 32 x 350mA 7135 model (11.2A total) with “SRK Special” STAR firmware. I’m swapping the emitters too, to give it wide-spectrum output. The three tints are 7B, 4C, and 1D, and I estimate it should add up to about 4700K overall with extra-vivid color rendering. Probably 3000+ lumens total, on turbo.

However, I’m waiting for four high-drain cells to charge first so I can get one final lumen measurement before I tear it apart. It might not happen until tomorrow, since I’m jetlagged and it feels like it’s about bed time already.

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but mine did not make it today, hopefully Monday. Sounds like you are doing it right with multi tint and new HD cells. Waiting for your review.

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Oh three different emitter tints…very interesting…definitely interested in the beamshots for that one!

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I’m guessing it will probably look somewhat like my BST-wide, which has lots of pictures up here:

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Yes illiminaria, cutting the output trace to generate zones is an option with this driver. They don’t have to be equal either. It kind of like slaving different boards to one mcu without having different boards.

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Only problem…the 7135’s are so close together…to zone the areas you would loose a chip on some of the outer traces to put led pads down

How many zones do you guys want? I can work on creating split channels if you like

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my stock driver had two, but four could be an option, with three probably used by most? I’m afraid if I requested a board with say two, a can of worms could be opened if you were planning to silk screen the zones? Or, maybe down loaded cutting masks to eliminate possible mistakes? See what demand you may get.

Yes, lifting then stacking or eliminating the odd 7135s would give you the pad room, no? I have a small nozzle for heat gun to zero in on one 7135 used on my wonky stock driver. By using low speed with foil mask and tweezers should allow me move the needed 7135, without repeated baking, if board came pre-stuffed like mine. Any suggestions welcome!

Thx

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I made a purpose build specialized 5*7135 with 3 zones specifically for a 3*XM-L SRK that I originally was going to put this 32*7135 in…but decided I was going to go ahead and rebuild it with a copper plate and XP-G2’s on sinkpads at 1750mA each emitter and make it a pseudo thrower…
Stock there are 5 chips per channel I guess stacking you could get 10*7135 per channel

Well Mattaus more or less did the entire re-design because for the life of me I couldn’t get the spacing down and made it look like a big ole mess so he fixed it for me and I just cleaned it up

https://oshpark.com/shared_projects/eblIPvqT

I am not sure I am running my reflow station too hot and burning chips or something…I reflow at 300C, once I see the solder melt I remove the heat on the component, anyone have suggestions on soldering with a reflow station (I don’t have a reflow oven…all I have is a stainless frying pan for one shot reflow ( built my first SRK board with it…but had a ground problem and couldn’t get it to work and I think I fried some chips)

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for those with the three LED SRK. Would not double stacking the 380ma 7135’s give you 3.8A per LED? Maybe for those that prefer lower power.

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Yes stacking is viable, it would give 10*7135 per channel 3.5A with standard 350mA chips, 3.8A with 380mA chips

Stacking is an art, takes some practice to get it right

I found that gently bending the leads down on the mating chip, a tiny dab of superglue to adhere the top chip to the bottom chip so it won’t move while soldering, then a good amount of flux on the pins helps drag the solder from bottom chip to top chip w/o it bridging over is the best method (not so easy on a Nanjg 105C w/ chips sitting VERY close together, on this boar the pins are easy to access and should make the task easier)

I might have to beef up the trace on the end of the “groups” to the pads if people want to push 3A~ out of each group, right now the trace is not very thick, I wasn’t thinking this would be a highly sought after build, I believed of it more as a specialized one shot kind of deal and not a uber high current build…1750mA really isn’t alot (but a XP-G2 at 1750 will run quite hot) and that trace should be able to handle it without issue…double that and now we might be pushing the limit

I really didn’t share this at first because I didn’t think you guys would be interested…

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I finished that mod I mentioned. It uses this board (32 x 350mA 7135, powering 3 XM-L2s at 3.73A each) and the result turned out almost exactly how I estimated. The step-by-step build thread (with lots and lots of pics) is up here:

So, thanks to your hard work and nice design, I now have a custom and much much nicer Skyray King. This is how it always should have been… it’s so much better now!

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Mattaus and Comfychair were the heavy hitters on the build…I was just the * cheerleader * in the endevor, I asked for the driver back when I first got into flashlights, and boy howdy did they deliver!

Did the driver board snug up firmly in the driver well, does it have good retention (as in not try to pop out) when everything is assembled…I might have used too thick a gauge and too not flexible enough wires on my build the first time when I shorted it and zilched some chips…but my attention to detail isn’t all that wonderful either :stuck_out_tongue: