D.I.Y. Illuminated tailcap

The S2 tailcap looks to draw about .5ma and one of these pulls 1ma and the other 5ma (the 5ma is dimmer though but I think that may be due to the LED’s, when tested before installing them they were much dimmer as well).

I basically can’t adjust the brightness as minute changes to the pot will cause them to not light up at all, I just feel happy when I get them to light up, there is maybe 1/10 or less of a turn for the entire “adjustment range” if you can call it that. The worst part is that the “working range” of the pot seems to move around the pot so it is nearly impossible to find it again.

What pots are you using? The ones in the OP? I might need to order some and see if that is the issue.

As it is I would just find the correct resistance and use resistors, it is easier then this.

I just ordered the cheapest 50k and 100k pots I could find on ebay. I get adjustment through most of the range, although the change isn’t dramatic, and there is a small section where the pot is essentially ‘off’, no throughput.

5ma is utterly ridiculous, I wouldn’t put that in a light at all. Most of mine draw 0.1ma-0.2ma, or 0.5ma if I want it really bright. You might just have some really inefficient LEDs or something?

The 5ma one sucks anyways, the green is “80’s power LED green” and dim. I have several others to pick from, might try some of those I just got in from ebay and see if it makes a difference.

The 1ma is brighter then the S2 now that I compare them so it seems to be working ok. These are both 0603 LED’s though but that should not make a difference.

I haven't look at how these boards are wiring the Pots. I think Pots are typically wired with a leg to ground and used as an adjustable voltage divider. So the more resistance you assign to the load, the less resistance is assigned for the excess voltage/current to flow to ground. So I would think low resistance pots would let more current flow through them, especially if you have the LED's dim.

We never connect the other leg of the pot, so there should’t be any extra drain there

Ok, I just built another one, these are all using the 5.3 bottom and top boards with a jumper on the top resistor pad and 3 LED’s installed.

This one was in purple (which looks real good BTW) and after playing with the pot for awhile I finally got it to light the LED’s with around .4ma.

Tested on the flashlight and it worked, both forward and reverse modes. Once again the final resistance was under 10K (didn’t measure it after putting it in the tailcap). The pot has virtually no adjustment window to work with and it is a real 50k pot when tested.

No idea why it takes so much less resistance.

The glow is VERY dim like this as well, only if you look would you notice it in a lit room. It acts the same weather installed in a light or run off the bench power supply. I can detect no shorts with the multimeter.

Quite strange.

I think you’re just setting them brighter than I do, and that’s causing extra draw and less resistance being needed. No idea why your pots seem finicky.

In most of mine you cannot see the glow at all with direct overhead light. Otherwise they are too bright with dark-adjusted eyes.

Your 560ohm bleeders should be fine with anything under 0.5ma draw. Nothing scientific about that (that I know of), just from experience.

To be honest I haven’t even tried to figure out how bright I want them, I just am glad when I can get them to actually come on, it is a matter of breathing on the pot and hoping it was enough to make it come on without over shooting and having to start over lol.

I will see how these look tonight and that will give me a better idea of how bright I want them.

The biggest issue I want to figure out is why it is taking so much less resistance in mine? What color LED’s are you using? So far I have used green and purple, they all have had a VF of ~2.3-2.5v, so pretty high and I am guessing why they need so little resistance.

I might do a red one next which should have a lower VF to see what it does.

Overall they look great, just the details I am trying to sort out.

So, you haven’t looked at them in a dark room yet? Maybe what you’re perceiving as “not on” is just as PD said “not visible” in a lit room. :wink:

Yeah, it could be the colors. I recently have used Red, amber, and yellow. And for those I had to get the 100k pots. I did a mixed blue and green one though and used 50k with it and it’s too bright. I’ve been meaning to switch it to 100k at some point (my X2R).

I adjust my pots on my bench with the power supply and usually without the silicone on top. If I have to cup my hands over the assembly and put my eye up close to see anything, that’s roughly the right brightness for me.

Either way keep on trucking, you’ll get it dialed in. This is why I recommend people lear for themselves vs just buying them pre-made everywhere.

Do you generally use 3 or 6 LED’s?

I just tried another one with 6x red LED’s and it is working a lot better. I was able to get it down to .22ma and it still light up although that is still only 10k ohms. I might be able to get it a bit lower but these pots are so touchy! A twitch too much and they stop lighting up all together, (verified by 0 current passing through them).

I can’t decide how bright I want them honestly. Part of me wants them bright enough to be able to see the glow while they are on the shelf, the other says that just bright enough to show me where the light is in pitch black is ideal.

I also need to find more springs, I am having to pull all the spares out of the convoy hosts right now lol.

I’ve done two with 6 leds (two color mix), and three or four with 3 leds. The single-color ones are easiest and seem to give the best efficiency for me.

One issue I have noticed with the header pins. the ground pin always wants to short out on the retaining ring. Anyone else have that problem?

I think I might have figured out a work around but building up a solder blob on the “positive ring” near the pin.

I don’t think many others have used the header pin versions.

I just keep the pin backed out a little bit so it isn’t right on the surface.

Yeah, I may start just cutting the pin down before soldering to keep it at the right depth.

I assemble everything on the top board and bottom board separately, including mounting the pins on the bottom board first. Then I do my testing and adjusting by applying power to the omten contacts and just sliding the top board onto the pins. Then when I’m satisfied I trim the pins and solder the top board on as the last step. It works for me.

Thats what I do as well, basically, I put the switch on while putting them together myself so that the hole keeps it centered.

My issue is the bottom side of the header pins where it contacts the retaining ring. The top side hits the rubber boot and that keeps it insulated in the S2+.

Yeah when I’m putting the pin in the bottom board I just only put it halfway in the via and solder it there so it isn’t anywhere near the surface on the other side. Does that make sense or are we talking around each other?

Yeah, same thing I plan on doing. Although I think I will cut the pin next to the “plastic spacer” on the pin to the right length to make things simpler. Or you can slide the plastic piece down a bit until it is at the right height.

I have to say, these are an amazing idea and work good. Just a matter of dialing in the components.

I think that since all the TA drivers use the same components it should be entirely possible to figure out a parts list for a “build and play” lighted tailcap.

On your pots, do they spin all the way around endlessly? repeating the same range each revolution? Or do they stop at the highest and lowest points? All the larger pots I have used stopped spinning (or clicked) when it reached the end of the adjustment window, thats one thing that is making this so hard.

Yes, with a dead spot of zero throughput at the end of each revolution