D.I.Y. Illuminated tailcap

Finally got around to adding a “proper” (Gen 2, Rev 5.3 style) tailcap to my Astrolux SS. I just got solder paste yesterday and decided to try that for soldering the LEDs. A little dot on all of the LED pads, placed the LEDs, and put it in a pan on the stove. It worked out wonderfully.

I did 3x blue LEDs and 3x white LEDs, with each channel behind a 20K ohm resistor. Used a 560 ohm bleeder on the Mtn FET+1 driver. Measured draw at 0.1 mA (my DMM only reads to tenths). Looks pretty nice, if I may say so.

In case I haven’t said it yet, thanks PD for putting these boards up on OSH Park. They certainly add a nice touch to my favorite lights.

Looks good!

I found 3.3k resistors give the best colouration and patterns but it’s abit bright for my taste whereas 6.2k resistor is a tad dimmer but it give some interesting patterns too.

I guess each colours depending on the current that drive the LEDs (i.e. Red colour needs high current flow whereas green need high current and blue and other colours are in between). Sorry i don’t have a multimedia to check and these are just base on my observation :smiley:

I guess there is no right or wrong answer and it’s just trial and error to pick whichever patterns / colouration fancy your eyes :slight_smile:

Looks great! Somehow I had completely passed over those 5.3 boards and didn’t realize they were only 2-channel. I’ve found myself wanting that in several lights but all I had were the 5.1 3-channel boards. So 5.3s ordered! Thanks!

Each of mine are seeing about the same resistance - 3k. So for anyone wanting to play with these color-changing emitters I’d say that’s a good resistance to start with. I agree mine’s waayyy too bright so I think I may open mine back up and try to physically filter it somehow. Its already terribly inefficient, might as well go all-in :slight_smile:

Here is another link for those RGB leds from Aliexpress. I searched it out because the ebay seller didnt ship to my country. Hope this is useful for some one.

0805 RGB Slow led @ AliExpress

And it is cheaper too :party: thanks for the link.

@emarkd: I have combined the 3.3 kOhm resistors on the ring with a switch board with pot, so I can adjust the overal brightness (but I like the brightest setting anyway :smiley: )

I would prefer much dimmer and more efficient, but I just can’t get the emitters to function properly at lower current levels. Even at ~3k total resistance, mine still eventually mostly lose blue, but at least they’re not just pulsing red like they were at higher resistance levels.

Speaking of, this tailcap was completely distracting last night when I laid down for bed. The green and blue is so bright I could see it reflected off of the ceiling. So I took it back apart this morning and added a disk of filtering material made out of this stuff, something I had laying around from other more “standard” light-dimming projects around the room. It went from this:

…to this:

…and is now much more like what I wanted. I mean its totally absurd, honestly — I’m running this thing at a full milliamp just for it to function properly, then mechanically filtering it back to a reasonable light level so I can actually stand to use it — but I like it so I’m keeping it :slight_smile: I’ll just have to be careful not to kill cells in it.

This weekend I got around to putting together a tailcap for my S41S (colored version - not my first choice, but when you get it for free… not going to complain).

Used 3x blue and 3x green LEDs on a Rev 5.3 board. Blue LEDs are behind a 20K ohm resistor, and a 39K ohm for the greens (and they’re still bright!). Driver is still the stock BLF A6, but with a 680 ohm bleeder added.

I’m looking for the easiest most efficient rev to add light to convoy s2+ tailcaps. I am using a fet+7135 driver. I think I’m looking for a single color light all controlled by the same pot. The less complex the better because I’m not the best at soldering. Can anyone help me?

The tailcap is pretty simple, the harder part is the bleeder for the driver so the modes work like they should.

Also depends on if you’re referring to the S2+ with a metal tailcap. While do-able, I ended up removing it from my S2+ because it was barely even noticeable. There’s just such a small area that’s visible, and it practically had to be viewed straight on. And only in a very dark room. I know others have them in theirs with a metal tailcap - emarkd comes to mind, see here. Looking at those pics again, either he had the shutter speed on his camera cranked up, or I did something wrong.

For mine, I like the Rev 5.3 boards and I just use the stock switch on it’s pcb. I don’t even mess around with pots, I just use the resistor pads. Like TA said, the bleeder can be a bit tricky. I have found the FET+1 drivers to be a bit easier to get the bleeder install on because there is typically more room. I’ve been adding mine on the spring side, just connecting it between the spring and the ground ring, scraping away a little solder mask if needed.

I have the silicon caps, so all good there. I will order some Rev 5.3 boards and stick to the default switch pcb. Can you recommend LEDs and resistor values for the LEDs and bleeder?

I also no longer worry with the metal tailcap, I have some right now and they are basically useless except in complete darkness and require many times the current even for that. I just turned them off for now, I might swap them out for a normal tailcap at some point.

Depends on the LEDs, honestly. But here are notes for some of them that I’ve built (all on Rev 5.3 boards). As far as bleeders go, I’ll be honest… I pick a resistor that sounds good and it’s always “just worked”. I’m sure I’m just lucky, but I’ve never run into issues with it. I consider all of them to be a nice, but not overly bright, amount of light.

  • 6 blue LEDs behind a single 10K ohm resistor (“103”). Measured drain installed on a 105C with 750 ohm (“751”) bleeder at 0.1 mAh (2+ years to drain a 3400 mAh battery). Link
  • 6 red LEDs behind a single 6.2K ohm resistor (“622”). Used with a 105C driver and 680 ohm (“681”) bleeder. Measured drain at 0.3 mA before installing (1.3 years to drain a 3400 mAh battery). Pic1, Pic2
  • 3 blue + 3 white LEDs with each channel behind a 20K ohm resistor (“203”). Used a 560 ohm (“561”) bleeder on a Mtn FET+1 driver. Measured drain at 0.1 mA. Plenty bright, seems relatively well balanced. Link
  • 3 blue + 3 green LEDs, using 20K (“203”) and 39K (“393”) resistors, respectively. Green still a bit bright. Used a 680 ohm (“681”) bleeder and a BLF A6 driver. Link

Thank you. I ordered a bunch of stuff and its on the way. Will report back when I need help or have something to show!

Nahh, neither of the above. Mine are built for the tailcaps with little other consideration. There’s no “seal” in there at all apart from a small bit of nylon glove, so there’s less filtering but also less waterproofing. On top of that I’m running them pretty strong, several mA each. They’re crazy-inefficient and I have to charge the batteries in them every few weeks, even if I don’t use them at all. But they are pretty bright. If you look back at my build info, you can see that I’m using a 200 ohm bleeder resistor on a driver that’s generally considered to not even need one. That’s just to get the power up for the tails. So yeah I can easily see them across my bedroom at night. They’re not nearly as noticeable in a lighted room though, for sure.

Finally put a lighted tailcap in my S41S. Placed a 750ohm smd on the battery side of the driver with a tiny drop op superglue so wont move and touched the ends with a drop of solder on my tip.

Thanks again budgetlightforum :+1: .

TA Bistro driver,BR=470R
Operation is not normal, bounce!?

What do you mean by bounce?

If the tailcap is too bright it will cause issues with reverse modes. I find that keeping it under ~.4ma works best with a 560ohm bleeder.

The flashlight is almost no action, press a few times, sometimes it will light.
The position of the switch is 1
Current limiting resistor is 20K*2
50K VR =0K