D.I.Y. Illuminated tailcap

I got mine from the same seller on ali express. Got it in not too long and it had a omten switch. It did mess with mode memory with both my mtn electronics driver and blf a6 driver. Need to figure out what resistor to get.

Ok, thanks for the feedback. I’m in no rush, I should order one so it’s ready when I get to it.

i have a quick question I suppose in the same realm of tailcap lighting. On the emisar d1 driver there is a unused pad for an indicator light, or other device but indicator is what im after. What type led should be used and how would I go about doing it for the e switch?

I think that whatever you solder in, it will need adaptation of the firmware too, the standard D1 firmware does not support an indicator led AFAIK.

I do believe you are most likely right. I just recently obtained the d1 and upon looking through this site found a post that revealed that info. So I wanted to do that modification if it was able. Oh...and it's an honor to have you reply to my post. I've watched and read most of your posts and YouTube videos

Do people actually watch those video’s? I should make more then :slight_smile: And it is a good practise here on BLF that new members are helped out with stuff, for we all want more flashlight lunatics, makes us feel normal :smiley:

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Do people actually watch those video’s? I should make more then :slight_smile: And it is a good practise here on BLF that new members are helped out with stuff, for we all want more flashlight lunatics, makes us feel normal :smiley:
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Yes, i did watch them when i was researching led emitter reflowing I also seen the blf a6 triangle fix. I believe that is what it was

It was a bit of fiddling around, but I finally got my illuminated tailcap working on my just modded Lumintop AA. New EDC is born :sunglasses:

What I used eventually:

*Lexel’s 15mm drvr with BistroHD. Had to be sanded down just slightly.
I Added 1*2.2Kohm (SMD 222) bleeder between + and middle of an AMC7135. The AMC had to be replaced, since the middle paws were missing on the ones from Lexel. I assume for clearance to the + terminal. Adding a bleeder over C1 is easier I guess, but I had already glued the driver on the pill. I wasn’t aware that a bleeder was needed on this driver :person_facepalming:

*XPL HI on noctigon star

*17mm Illuminated tailcap from fasttech. Replaced the leds with 2*0805 red’s and 2*473 SMD resistors.
The transparent spacer had to be sanded down a bit to fit.

*Green transparent tailcap from kaidomain. Nice transparency and no problems with tailstanding.

*Keeppower 14500

The tailcap is perfect for finding your light at night. Basically invisible in daylight. Just how I like it.

I couldn’t measure (0.000A) any current through the tailcap, so it’ll last at least 2,5 months on a full keeppower.



I’d like to make a couple of single AA lights with illuminated tail caps for my young kids.

Apart from the Tool AA (thanks Dutchee) can anyone recommend a single AA or three AAA light that takes s 17mm Switch PCB?

I’d prefer no strobe and not too bright. I was originally planning to give the single mode SK68s (with a resistor in series with the LED, but I think they have press-fit switches.

^ mind that a lighted tail the way it is done in this thread only works on li-ion cells because there is no voltage boosting for the tail leds going on. You might get away with a 2xAA light and red tail leds.

Hello all,

Here's my take on the lighted tailcap - a simple version (no microcontroller required!) which has two groups of LEDs and two configurable threshold voltages, for example 3V and 2.7V.

When the voltage is above the first threshold, the primary colour lights up (e.g. Blue). When the voltage is between these two voltages, the 2nd bank of LED is switched on and the first switched off (e.g. Red) - this can act as an indicator to recharge your battery! When the voltage falls below the 2nd threshold, both LED banks shut off to increase standby duration.

Also while at it, why not convert your switch to a FET switch instead?

You can achieve single milliohm switch resistances depending on the FET used. The FET board has an onboard tiny rechargeable battery, so servicing is not required once installed! This may be useful for those wanting to increase the durability of the tail switch, esp. on lights with high battery currents.

Please feel free to check out this thread for more information, including OSHpark projects so you can make your own:

https://budgetlightforum.com/t/-/50404

Hopefully this is useful for some people! I know I'll be using it in my lights.

Thanks djozz, I’d forgotten about the voltage issue. :person_facepalming:

I suppose I could use a 14500, but want to avoid letting the kids use Li-Ion cells unsupervised.

A 3xAAA light should work. I put a lighted tailcap in a Sofirn SF30A last night, but it’s a little bit bigger and a lot brighter than I’m hoping for.

Thanks for sharing your designs loneoceans! :+1:

Building them is beyond my capabilities at the moment, but as soon as my skills are up to scratch I want to put them on all my lights. :smiley:

This is clever :+1:

Is yellow doomed for being inefficient (ie. high current)? I’ve tried 2 suppliers with similar results, and expecting another supply of 0805 yellow LEDs any day now.

Here are the milliamps for my various tailcaps. The brightness of each is about the same, per the perception of me and my family. If one was considered brighter/dimmer, I would change the resistor value accordingly.

  • Orange (.56), yellow (.99), green (.07), blue (.21), pink (.26), white (.33)

As you can see, the yellow current is much higher than the others. I like the various colors, but don’t like how inefficient the yellow is. Maybe I’m having bad luck with where I’m buying them, or perhaps yellow is just inefficient.

Nice measurements!
Yellow is indeed doomed, they are inefficient. I like the colour and I have used them for the switch of a C8F, looks really cool, but they drain the battery a lot faster for the same brightness as other colours. Blue and pink and white have similar current because all three are a blue led. Orange is also pretty inefficient, while red (not in your list) is much more efficient, I expect it to end up at .20 in your list.

Warm white is good alternative and it's few times more efficient.

Didn’t know red was more efficient than orange djozz - so I may swap them out, or add red to another flashlight. And good tip led4power to use warm white instead of yellow - I may order some. When my new yellow LEDs arrive, I’ll see if they are any better.

I did try putting some layers of yellow plastic sheets over the white LEDs, but it barely made the tailcap yellow. Certainly not as yellow/gold as the yellow LEDs.

Another great BLF innovation.
I tried this on a Convoy S2+ with 18350 tube. Took awhile to get the right combination, thought I’d share what worked for me.
I’m using a BLF X6 driver that comes with a attiny25 and Bistro as the UI.
I used the lighted tail switch from fasttech.
The driver has a 470 ohm bleed resistor already installed. The lighted switch has 2- 330 ohm resistors and blue led’s already installed.
These two together would not work correctly running Bistro. It couldn’t detect the off time, no memory and no medium press.
What finally did work, using the 330 ohm resistor from the switch on the driver as the bleed resistor and changing both switch resistors to 10k.
The” banggood lighted switch”:Astrolux SC / SS / S2/S3 BLF X5/X6 Taschenlampe 2 LED Beleuchtung Schalter für DIY Sale - Banggood Deutschland-arrival notice-arrival notice may work as is, from the pics it uses 2-15k resistors.

Should work without a problem

I use two 22K resistors and two blue LEDs on the original switches of BLF X5/X6 kit (wood box)