D.I.Y. Illuminated tailcap

Got it, I’m going to try that out later in the week. Thanks for input everyone.

I’d like a floody mule type light with a lighted tailcap for the nightstand. Can anyone recommend a good host for conversion or are there any lights out there that have lit tailcaps out-of-the-box?

The recent Manker X6/X5 group buy lights have the lit tailcap. There are still some available, IIRC, and they are now able to be bought separately (at first sold as a pair only). Also, there is a new Astrolux version of the same. These are very throwy lights for their size, but the only lights I know of that have lit tailcaps out-of-the-box. You could convert one to a triple or quad to get more flood, using a floody Carclo optic.

That’s where I’m at I think: modify an X5 to triple or find a floody mule type light and modify to have a lit tailcap.

It seems that the triple mod on an X5 will require a custom pill or machining to fit - or is their a simpler way I have missed? My thought was it may be easier to find a suitable host and add a lit tail, not sure…

This is destined for a child’s use, so the perfect solution would be to only have one low setting (no other modes).

To me the easiest way I can think of for you would be to get a a convoy S2+ that has the normal silicone instead of the metal button. Then you can use the Carclo 20mm TIR’s to adjust the beam profile how you want it, and it’’s not too hard to do an illuminated switch in a convoy, all you need for tools are a soldering iron and tweezers. The S2+ also takes 17mm drivers so you could get a single-mode single-7135 driver from fasttech or Richard or wherever.

I second PD here.

Rock on, I appreciate the tips. Just sorting out the details now - a little off topic, but I promise I’ll get back :)…would this optic work with stock XM-L2 LED as a diffuser on the S2+ or am I better off just building a triple LED with Carclo frosted wide spot ?

I wouldn’t go through the work to make a triple unless you want higher output than you can get from a single emitter. The first optic you linked should work fine, though I haven’t tried it personally.

Not looking for high output at all, but I would like a nice floody beam.

So, my options would be to use the “stock” pill and simply change the driver board and add this optic or build a new pill using something like a Nichia 219B Triple on 20mm Noctigon and a Carclo frosted wide spot .

The only advantage to the latter would be a little better color and (possibly?) a better/floodier beam? I suspect I will drive at 100% from a single 7135 chip (380mAh) - would one solution offer lower output than the other?

You could also put DC-Fix on the lens of a tube light. It’s not quite as smooth as a frosted lens or frosted optic, but it’s quick and easy and pretty effective.

The hard part is getting the driver and tail light adjusted to work well with each other.

Well doing a triple always adds cost and a bit of time. I think you can get plenty of flood from a single optic, and if you want better color rendition you could always just swap the emitter for a single Nichia.

I won’t keep trying to talk you out of a triple, it just don’t think you’ll gain anything from going that route except for maybe some “cool factor”

Yes, but in this case a single-mode driver shouldn’t have any trouble at all

Thanks again for all of the advice, much appreciated!

I’m liking the size of the 18350 version S2+ for this application in blue, but it appears only the gray and black come with the rubber tailcap. So, to lego something together in blue I’m looking at the following items for the host:

Host =
Convoy S2+ Host (blue)
18350 Tube (blue)
Convoy S2+ with LED gray (for rubber tailcap)

For the LED driver, it would be nice to get a flood with one low light mode (like 10-15 lumens or less). I’m looking at a Nanjg driver with one 7135 chip (380mAh output) programmed with guppydrv which can be set to one mode at 100%.
LED/Driver/Optic =
LED - re-use XM-L2 that comes in gray S2+ host
Optic - 60 Degree Flood
Nanjg Driver w/ guppydrv firmware and (2) 7135 chips removed

And for the tailcap I’d like to go with purple LEDs (will the UV emitted potentially be harmful? should I use one red and one blue LED instead?):
Lit Tailcap =
PD68 Lighted Switch - 17mm Rev 3
Omten 1288 Switch
Spring
Translucent Tailcap (white)
Purple 0805 LEDs x 2
nylon or acrylic washer

  • some 0603 or 0805 resistors for bleed resistor on driver and to adjust LED brightness level at tail

See any glaring problems, omissions, or have better recommendations for any components?

I don’t know if you can flash drivers, but if so, you could use ontime-based firmware which wouldn’t require a bleeder resistor and would thus give you higher efficiency and runtime while the light is on.

I’m not aware of a way to make guppydrv run with only one mode if you want that mode to be lower than 100. A single 7135 chip at 100 will make like 140 lumens, not 10-15 lumens. However, a couple simple changes to STAR_1mode could make it run at ~12 lumens instead of full power. (Basically, comment out “MODE_TURBO”, uncomment “MODE_LOW”, and set it to like 20. Maybe set LVP_MIN a bit lower too.)

Thanks for the tips - sounds like not too many people want/need a nicer tail lit light with only one low low mode :).

I’ve done some programming and similar work, abut never flashed flashlight drivers. That said, I’ve looked into it a little and I believe I could give that a go if there is not an “off-the-shelf” firmware solution that will achieve the desired results.

I follow your code comments above and found the referenced file in your linked repository - thanks for your contributions to flashlight firmware! One part that lost me above was the term “ontime-based firmware,” can you explain or point me in the direction to what this means? Is Star_1mode ontime based?

Cheers,
David

Oh, ontime-based means it decides on how to change modes based on how long the light was on, rather than how long it was off.

It’s easier to understand offtime-based lights. You turn the light on, it comes on. Tap the button quickly and it goes to the next mode. Turn the light off for a long time and next time it’ll come on in the first mode again (unless you have memory enabled, which will make it come on in the same mode as last time).

With ontime lights, it doesn’t know how long it was off, so it does something else. If the light was activated within the past second or so, another button tap will advance it to the next mode. After a second passes, it “locks in” and the next press will make it go back to the first mode (or use memory).

This matters because the lighted tailcap tends to interfere with the offtime measurement. The tail pulls current through the driver even while it’s off, which prevents the components from discharging normally. So we add a bleeder resistor to let this current pass without affecting the rest of the driver. That works, but it has the side effect of reducing efficiency while the light is on.

With an ontime-based UI, the bleeder is unnecessary because the driver doesn’t care how long it was “off”. You can use a lighted tailcap with no bleeder and it won’t break the interface. The main consideration there is that it might have higher resistance while using the whole driver as a “bleeder”, so the tailcap resistor values might need to be tweaked differently.

Anyway, it just means, since you only want one mode, you can get higher efficiency by not using a bleeder. But it requires using firmware that doesn’t care about measuring “off” time.

Got it - thanks for explaining, that makes perfect sense.

It’s about time I learned something new, so I’ll set myself up with the SOIC8 clip and programmer to flash the chip. I’d like to go with an ontime based UI and avoid the bleed resistor, I skimmed the code of Star1_mode, but nothing jumped out at me - is this firmware ontime based or can you point me towards a suitable (one low mode) firmware that is?

Oh, yes, STAR_1mode is ontime-based.

Not that you need ontime or offtime for a 1-mode light. It’s just the only 1-mode firmware I’m aware of. Someone wanted to modify STAR for this sort of thing a while back, and the changes ended up being somewhat non-trivial, so I made it available as a separate project. It could definitely be, um, smaller, though. Not much logic needed for a single mode, so a lot of the code in it is unnecessary.

It defaults to only using turbo, with a turbo step-down or ramp-down, but that’s not hard to change. It also has low-voltage protection, which is probably a good thing to leave enabled.

Great, much appreciate all of the detailed information. I’ll plan to use a STAR_1mode slightly modified firmware and forego the bleeder resistor.

I’m looking forward to this little project as well as learning the flashing process for these Atmel chips. I’ve studied up and downloaded all the relevant software - I appreciate the code and guides you and others have provided over the years, there’s a wealth of information out there!

I’ve got the programmer, clip, and all of the flashlight/tail parts pieces on order. I’ll keep this thread posted :).

Cheers,
David

Nice runtime! 8)

Someone suggested leds like these way back in this thread and I found some at tme-eu, but without documentation what they actually +do+. Hoping for that slow fading rainbow effect, I just made the lighted ring. Well, I just found out what the effect is, so far for the slow fading , I'm not sure if this one is going to make it into a flashlight

The annoying tailcap - YouTube