TK's Emisar D4 review

Got my first D4 in a couple of weeks ago. Ordered from intl Aug 31, got it about three weeks. Went for a grey (green not in stock) with XP-G2 S4 5D 4000K partly for cost, but mostly since the XP-L and Nichia were only available in 5000K at the time (5000K is too cool, if I have a choice, and 3000-3599K is ideal). Also, I have no interest in pounding Nichia 219s to death when I have a nice Jaxman E2L 4000k triple (2.1A?) if I need a lot of high CRI light.

Lot of info in this thread about XP-L and Nichia, very little on the XP-G, and even less on the 5D, even though I think there was a list where it came in 3rd or 4th most popular. Bought a clamp meter that cost almost as much as the light, which makes both items a great deal. I get a bit over 11A with fresh 4.2V 30Q or HG2, and about the same with a 4.1V Sanyo NSX. Suits me. I stay under 3A per emitter, and it's still total overkill on turbo: eye searing (closed eyes), skin burning (the beam or the light), and fire starting (if the paper is a dark color). I get 11s turbo before 1st stepdown using a 49C thermal setting. 59C, but the light reads about 10C too high. The outside of the light gets to 52-59C, depending on conditions. Got 8A with a generic 2500mAh cell, 8-9A using a 20A DMM with short 10awg leads and internal 10mOhm shunt.

I'm a total Zebralight nut. SC600, mkIII HI, mkIV Plus, SC60,62,64. Not counting the AA ones, two of which are high CRI (the XM-L is the worst white-wall tint I've ever seen, so I can see why Emisar isn't using Cree for CRI). I love everything about them except for their complete disregard of my battery terminals in the SC52,53, and 64. The 63/64 really should use the D4's tail spring. I'd suggest it to ZL, but I've already complained multiple times about their battery abuse, and I have to believe they know about BeCu springs. In the meantime some 0.1mm copper foil on the abusive spring suffices.

So, I just got the D4 because it was a cheap experiment, and so many people raved about it. I'm almost embarrassed to say, like so many in this thread, that the ZLs are all on the shelf. The SC64 is a much better EDC because of the size and the clip (even if the clip does wiggle a bit), and the Plus is effectively as bright as the D4 with much better efficiency, temperature control, and moon modes. But, the D4's tint is so much nicer, and the UI is so much fun. Reminds me of my old keychain Photon Freedom, a SotA 10 lumens back in the day. I don't know if it's the tint or the UI that's more of a factor, or the feel in the hand, but I really love the D4. To throw in the iPad-size work bag, I found a LED Lenser PX20 (red/white LEDs) holster fits the D4 perfectly. Shouldn't need a tailcap lockout, but it really would melt the black nylon if turbo came on.

So, I love it, but what's a one-sided review. So...

To gripe, I'm not a fan of the well-executed but too-simple driver. ZLs efficient 12V boost driver is incredibly impressive engineering. The D4 is just, well, something that can be easily put together with off-the-shelf parts. The mechanical part of the design, especially the springs, took some ingenuity, though. Maybe as much as ZL, given the price. And the springs are flat-out superior to ZLs struggle with too-stiff springs and pogo pins. I don't know why that's given them so much trouble. The body design is basically a ZL copy made easier and cheaper to manufacture. I'm not griping about the $35-40, though. $90-100 ZLs do give me pause, $60-70 ones are worth it.

For the UI, the only real complaint for practical use, is that it memorizes turbo if you shut it off in that mode. I like the three blinks in the ramp, and really don't get the analogy with a car where the engine stutters at efficient RPM. It's not a car. It has nothing the least bit in common with a car. Even calling it a "hot rod" only makes sense to me in that it is cylindrical and if you run it long enough on high, it's like holding on to the wrong end of a torch (the flaming kind). Cars have lots of controls and indicators. This has a button and a light. And, if we're going to gripe about questionable turn-off times, the dark time to turbo after a double click while on makes a lot more sense to me. The double-click event and timeout explanations cover / justify that, though. The tactical mode is completely pointless, since a couple of flashes and it's off doing something else. I'd ditch it entirely and use 4 clicks for lockout.

I'm not planning to get another D4, but 9/25 I ordered a green D4S with 4000K XP-L. I'd have much preferred 21700 or 2x18650 to 26650, but it looks like a comfortable size. And IT HAS AUX LEDs. I wasn't even considering it 'till I saw a picture with the cyan pseudo-tritium, after that I couldn't order fast enough. I could see maybe another D4 if green or another _smooth_ color comes out, like purple, and if some other 4000k (CRI?) option comes out. Nichia is just a bad match for a linear driver, but maybe XP-L, preferably Samsung. Don't expect either, any more than I expect a 21700 tube for the D4S.

So, the light and reading all of this thread have been a ton of fun, thanks BLF.

On the subject of children: one suggestion I would make is to put a frosted lens in the light. I’m not mad keen on the idea of diffusion film, since a child might find a way to remove it.

If you have a spare lens for your light, you can frost it with fine wet-or-dry sandpaper. Just sand it until you’re comfortable with the result.

As others have said, a Convoy S2+ with one of the less powerful drivers might be a good option for children you can trust not to mess with the Li-Ion cell. Convoy sell spare lenses, so you can get an extra one to do the sandpaper frosting thing on.

Other ways to reduce beam intensity are to use a larger LED - XM-L instead of XP-L, for example - and to use an orange-peel reflector.

For small children, I’d definitely stick to low-powered lights that use AA cells, and I’d still be inclined to frost the lens for good luck.

The D4 has taken the place of my ZL SC62d for EDC. I prefer the ZL size and stock clip, but after adding an Overready clip it rides nicely in my pocket. The tailcap has a tendency to scrape the back of my hand when I reach in the pocket but negative reinforcement has changed the angle that I use when reaching in.
I’d prefer to be able to carry the ZL but I’ve got Anduril on the D4 and find it perfect for my needs.

indeed.

Photo of D4 with clip?

My photo wouldn’t hold a candle to emarkd’s photo posted earlier, here it it:

Long story short :wink: I agree the xpg2 5D is the best emitter choice for the D4.

That is fixed in newer firmwares, including the one the D4S uses. It does not memorize moon or turbo, unless the user ramps to that level the long way. Getting there via a shortcut does not override the memorized level.

If you are interested, and don’t mind a little soldering, you could upgrade your D4 with much more interesting firmware. More info is at the Link in my signature.

This is also fixed in the newer firmware (Anduril), which uses 4 clicks for lockout.

About the only time I actually use tactical mode is on the BLF GT. It’s fun to set that to full power and then put it in tactical mode. Then tap the button and it goes “pew pew pew!”.

Any chance of getting a tiny speaker placed in the light that actually has “pew pew pew” sound effects? a light saber sound will also be nice

Shrink this circuit down:

https://makezine.com/projects/make-35/raygun-vector-weapon/

I agree with radellaf . I find myself carrying the D4 except when working. I don’t want to scratch it up in my pocket with my keys. It is just so much fun and practical at the same time. If I am outside by the firepit, I can light em up with turbo or just use it to find the beer. I would prefer USB charging for a travel light though, just for convenience. Might get a second one in the future or the D4S. Mine is the XP D2 S4 3D version.

is there any mods required for the clip ? Anyone using other clips?

Yes. A ‘captive’ clip like this won’t allow the tailcap to thread fully onto the battery tube. This creates a gap between the end of the tube and the tailcap’s board, so there’s no electrical contact.

A washer is needed to fill this gap. Options include a wave washer, copper crush washer, or even a piece of solid copper wire or paperclip formed into a circle.

I use Solarforce clips on my Emisars. They’re a bit bulkier and squared-off than the Overready clip, but less expensive.

I made wave washers out of some flat brass washers I found in my junk drawer. I used two pairs of needle-nosed pliers to create the waves, then sanded the peaks to increase the contact area.

The Solarforce clip hole is slightly too small to fit over the battery tube’s threads. I used a Dremel with a sanding drum to open it up slightly. I also ground off the lanyard ring. I removed the o-ring, installed the clip, then re-installed the o-ring and tailcap.

emarkd had to Dremel his Overready clip to fit, too.

I made my washers slightly thicker than the clips’ mounting rings, so the clips can be rotated.

I don’t mind the moon memo at all, but yes, I noticed the D4S had some user-requested changes in its simplified version of your new firmware. I’m amazed at how far a one-button interface can be pushed. Certain other products seem to resort to bluetooth remote control long before this, but then they’re over $100, mostly rubber not metal, and have much bigger markets.

I am interested, but not too excited about what it takes to remove the driver and buy enough bits to grip the chip. I’m an EE and electronics hobbyist so I certainly could do it and won’t rule it out, but it’d be a relative lot of stuff to get that as far as I know I’d never use for anything else. And, I don’t think I’d get it back together quite as nice with the paste and everything. I think it’s that I only like taking apart stuff that is an extra one, something I don’t care about breaking, or don’t intend to ever put together. I’m not into modifying one unit of something I like. The D4S with the exposed pads is a more likely target, though. The lightning and candle features I could add are definitely tempting.

If it shows where my interests lie, I was willing to spend about the same money as the flashing tools (I think, ~$30?) for the clamp meter. I figure I will have other uses for that, though. Maybe. Wish it would measure AC power without having to clamp only one wire in a power cord.

I wrote a few hundred lines of C firmware for a Cypress PSOC based USB light meter, but when I look at the Arduino code for the instrument at my new job, it’s pretty intimidating. I see it call “avrdude” at some point and thought of this thread. I still like 1990s BASIC with line numbers. Did everything I wanted for much more complicated programs than these, and never gave me bugs from unintended variable type casts or overflows.

Anyway, the flashlight isn’t for tactical or practical purposes, and I have lots of light-up toys, so I’m happy to have it for what it is in stock configuration. If I ever look for a 2nd one, though, or a new version (D4X?), and expert-mode firmware is a paid option, I’d probably go for it.

I appreciate for the welcome-backs and the info folks!

Earlier today I read through 20 or so pages of the Attiny25/45/85 FW Development Thread ranging from a few pages before my last posts in that thread up to page 39. This seems to have covered most of DEL’s work on adjusting the decoupling as well as the foundations of deleting the voltage divider. I’ll do my best to catch the rest of the way up on that thread soon.

@Tom Tom - your dropbox link did not work for me :frowning: If possible I’d love a link to a post with a current circuit diagram and/or a list of current component values. Catching up on the FW development thread has helped and I probably have a good handle on the changes that have been made but it never hurts to be sure. The high quiescent current of previous designs is actually what kept me away from e-switch lights in the past. I just wasn’t comfortable with a light being dead in a handful of weeks if I failed to do a mechanical/electrical lockout.

@Dale - I agree, gotta be sensible.

@TK - Thanks :slight_smile: Rather than continue to derail your review thread I’m going to try and get my thoughts together over here: wight catchup

It’s amazing what one can do with one pixel and one button.

If you think the white version is fancy, you should see the firmware which uses a multi-color pixel. :stuck_out_tongue:
(rainbow lightsaber driver, lets the user build their own color patterns similar to how an analog synthesizer lets musicians build their own unique sounds)

Don’t worry, that train left about 4000 comments ago. :slight_smile:

I think half the fun of synths, though, is all the analog controls. I haven’t played with any iPhone or SW synths, but I loved the MiniMoog at Radio Shack back in the day. The 2014 documentary “I Dream of Wires” was both nostalgic and eye opening (to the fact that dev work is still being done!). One button color pattern making would be something to try.

My only experience with multicolor was the functional but so too-simple 4sevens Quark RGB (no color mixing, hideous 18650 tube, but the RGBW MC-E was so cool), and the Technology Associates Rav’n 5mm RGBY 3-button 3-AA box with a big-ol’ DIP uC in it. Neither did mixing or had more than one brightness for each color, but they were cool. There was also a button cell keychain Rav’n which qualifies as 3-color 1-button and I think mixed. If I was going to do the hardware design, though, I’d have to use 4 SMPS current regulated supplies. PWM is, to me, digital software intruding into my analog hardware. Not that the “S” in SMPS isn’t sort of digital, but once you’re in the MHz range, without RF circuit layout, digital starts becoming analog. Anyway, when I’m out of work, I don’t have the budget or inspiration to develop my own flashlight (or a workbench), and now that I am working, I don’t have the energy to do more than some battery and flashlight testing for the fun of it. So I’ll just enjoy what’s out there and affordable. Affordable is relative to income, of course, but just out of principle, I can’t ever see spending over $100 on a light. I think I did for a Surefire Aviator A2 back when THAT was the height of technology, and it is still a wonderful shelf-museum piece. Not sure what the “budget” in BLF means. From this thread it seems like $200 for a light would be unthinkable, but four $40-50 lights is, well, it’s only $40 at a time, right?

As far as kids and lights, depends on the kid. I could have handled a D4 and LiIon charging at 8 or 10. A good portion of adults, most evidently those who like to vape but don’t care to learn anything about electronics, shouldn’t be trusted. Then again, I did melt a carpet with a 7W Christmas lightbulb. As for eye damage, just going by casual knowledge, a flashlight doesn’t begin to compare with even a low-ish power laser. The D4 certainly isn’t going to burn your retinas in the fraction of a second you can look at it without wincing and closing your eyes, only to find it still is uncomfortable with them closed. If you stick it a few inches from your eyeball for several seconds, though, you’ll probably burn your iris, and eyelashes, and eyelid, and it’d really hurt. By the same token, I’d hope kids don’t stick their noses a few inches from a stove burner.

My sweetie does have a 4x7135 convoy C2, but remembering that it has 3 modes is about the limit of what she wants to learn about a flashlight. i.e., You turn it on and it lights up, and there’s something wrong with the light if it’s more complicated. It’s not smarts, it’s attitude. I handle charging or replacing the battery. If I were to give a light to any non-flashlight person, of any age, it would not be 18650. Internal LiPo, maybe. AA or two? Definitely. Sofirn makes a lovely AA light, maybe the SF10. or a Fenix E05. That’d be about it. Hard enough to get someone not used to it to charge a NiMH. Come to think of it, USB charging would be easier to get them to do, assuming they charge something like a phone or camera on a regular basis. USB internal 18650? Eh… maybe.

I always kinda wanted a Techass Rave’N. I still have an ErgoXRay kicking around.

Synths are great fun. I prefer the hybrid variety though, mostly-analog signal path with digital controls and digital effects, so it can get a rich sound but also can load and save presets and automate tonal changes over midi.

But, that said, I also have a Microbrute… which is pure analog to the extent that it uses CV controls, and patches must be dialed in each time they’re used. Sometimes it’s fun to just loop a pattern while painting a rainbow of sound with the knobs. Other times I use it in more carefully-composed songs, usually as a bassline.

Anyway, I’ve also found analog sound synthesis concepts useful for lighting purposes. The candle mode in Anduril is implemented as a 6-oscillator synth where three of the oscillators modulate the other three. And the lightsaber UI works as a 2-oscillator synth moving through a 2D colorspace (hue and brightness), with one wave oscillating between two arbitrary points in the space and the other wave oscillating strictly up and down along the brightness axis. It’s not the fanciest synth design ever, but I wanted to keep it relatively simple since there’s only one button to work with. Despite that, it’s still far more flexible than any other saber engine I’ve encountered, and the 12 profile slots almost feel like they’re not enough.

The interface for that is:

The current pattern is shown real-time during configuration to make it easier to adjust by feel.

Thanks goshdogit. I will hunt for deep carry clip.
Won’t have to be captive or pretty

TK, I cringe to think of the relevancy of “pew pew pew” should that cat backfire…. :wink: