D.I.Y. Illuminated tailcap

Well crap! I have an S2+ that is my EDC and I decided to try out one of the new washer replacement tailcap boards. Got it build, it ohmed out well and all of the leds lit on my bench supply. So, I took the 2 led switch out of my S2+ and replaced it with this…
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It lit up and worked well, for a while.
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Then I lost mode switching! If I very quickly lock out and lock in the tailcap it will switch modes. But, if I half press the reverse clicky it will not switch modes to save it soul now.
What the hell? My meter sees an open on a half press with it mounted in the tailcap. I used 4.7k resistors, so now it would be seen as 3*4.7k in parallel?

Any ideas? Can a switch go bad this way?

Matt

Well, after spending more time with this… the 4*7135 in this light does not like this board even though it is currently working with a 2 blue led board. But, this board works fine in my JAX C8 Mini with an 8*7135 board. These things could lead to drinking on a bad night! It also did not work properly in the BLF X5, mode changes were wonky.

I finally got boards built for all of my colored S2+ lights.

All are the 14mm v5.1 ring boards used in place of the metal washer that was in there. Looks like this all mounted up:

All of them are using color-matched 0805 emitters, obviously. Resistor value varies greatly between them, from 5.9Kohm for the blue down to 1.5 Kohm for the red. Yes that means the red isn’t very efficient, but I didn’t build them for practicality. They’re fun! All of them have MtnElectronics 105C drivers with varying numbers of 7135s depending on the emitter in the light, and all flashed with GuppyDrv. They all work as expected after I got the bleeder resistor value worked out, 220 ohms in my case. I connected that bleeder resistor directly from V+ to GND right here:

Since I had to remove the original black rubber piece that provides all the waterproofing in the tailcap of this light, I added some nylon rubber I cut from a disposable glove. I put it directly under the switch assembly, like this:

I haven’t tested it yet so I have no idea if that works or not, but it looks…reasonable. Would probably be better without the crease in there but they all did that when I screwed them down.

I’ve shared this before elsewhere but here’s a bonus shot of the other end of these lights.

This is fun! Thanks PD and everyone else involved in this project!

Nice, thanks for the pics!

The green one looks especially nice

Really goodlooking! :sunglasses:

Thanks, the blue one is nicer than it looks in the photo. It slightly overexposed here because its really still the brightest of the bunch, but I’m kinda tired of tearing it down and swapping those resistors. :slight_smile: They’re not exactly in an easy spot to get to on those boards. Maybe I’ll increase those another step or two one day when I’ve got nothing else to do. But for now I’m very satisfied with how they turned out.

I need some help… I have rev. 3 board and for some reason I can’t get 2 lights to work on the board. I can only seem to get only one of the leds to light up. Below is a picture of the switch side of the board. Any insight would be appreciated.

Really good looking tailcaps there emarkd

Vinte did you mean to put the LEDs on the resistor pads and vice versa?

No, I didn’t. So I have the LEDs on the resistor pads and the resistors on the LED pads? No wonder it’s not working right! Thanks.

Afiak that isn’t the reason that it isn’t working, a resister can be placed before or after a LED. (Correct me if I’m wrong)

Did you place the LEDs the correct way? Positive on the + side?

You’re right, but I don’t remember exactly how I had the traces laid out on that board, so using the resistor pads I don’t know the polarity. However, the polarity is marked for the LED pads

How can you tell which side is positive (since it so small)?

It seems that one of the LED was mounted in reverse. Usually the end with green mark is the cathode (negative). Correct the way of that LED did not light up.

So the side with the green mark attaches to the board? Or the side with green make needs to be oriented in a certain way while being attached to the board? Both LEDs are attached to the board with the green side down.

- so I found a diagram online showing which side of the led is positive but it still only one led lights up

I think that the left led has to be reversed.

I found the photos at #592. Both of the cathodes of the LED are pointing to the centre. So your LED at the right side was mounted in the reverse way.

This is how I see it.
The positive side of the right led pad is at the bottom, so the cathode has to be pointed up. Like the way it is now.
But the other led pad is reversed, e.g. the positive is pointed up. That led has now the cathode pointed up (‘at the positive pad’).

thijsco19, you are right. The cathode of the LED at the left side should be pointed down ward. My distake.