Is an illuminated tailcap possible?...... Solved?

I don’t think so. If you always want it to be “on” when the light is turned “off”, then make this “moonlight” mode to be your “off” mode. You wouldn’t need another LED, or extra wires, or a true “off” mode in that case. When programming your modes in the firmware, program this one to be sequenced the same way your normal “off” mode would have been. As for pointing it toward you, I don’t think you’d need to, but it would be the same if it was a tail-cap LED.

If I didn’t run a wire, and just did it as I have in the diagram, I assume it would turn on the driver and complete the circuit so the smd led would be lit, and then it would supply equal current to both the led in the tail and the main led, depending on the mode the driver is in and the resistor used. Does that make sense? Or does the Attiny require more amperage than that to turn on?

I would have to look into it to see how hard getting rid of ‘off’ would be. With a tail led, I can just headstand the light on the table and the whole rubber tailcap should glow in all directions, instead of laying it on it’s side pointed towards me.

Tail cap is going to be really hard. Why not just use some glow paint or break down and get the Tritium vials and put one in the tail cap. Just a drill hole and slide in the thing. Glow paint would be easier and could be removed or repainted if necessary.

Hmm that glow paint looks interesting. I didn’t realize it could glow for that long. Have you used that glow paint? do you think it would work if I painted the inside of the translucent tailcap? I’d be worried about it cracking.

This is really just a thought of “can it be done?”

It really isn’t necessary.

If you think it might crack, why not paint it on the solid parts under the translucent tailcap, or even get a GITD tailcap.

yes, my magicshine bike light has it. But the switch is a separate unit with wires going towards it.

the space in the flashlight tube is usually too scarce to run wires in the space between the battery and the tube, and there’s a risk of shorting the wire.

However, protected batteries actually do something similar. The protective circuit is at the minus pole, and there is a thin tin sheet delivering + pole to the protective circuit on the minus pole.

Use gitd o rings on the body, gitd tail caps, glow powder mixed with epoxy filling a groove or a hole, tritium vials, a servant that holds your light for you. I like that last option best.

Why would it be necessary to run a wire from the positive side of the cells down to the switch?

Wouldn't the positive side of the led just connect to the flashlight body and the negative to the bottom of the cell? Any point in a circuit is a point where electrons are flowing. If the driver didn't have enough parasitic leakage, couldn't Pilotdog68 just connect the limiting resistor from some positive point in the driver to ground?

I have more GITD tailcaps than I could ever want, but they only glow for about 20 minutes after the lights go out, and not very brightly at all.

Again, the light in the tailcap isn’t neccessary, I just thought it would be cool if it could be done.

I really don’t want to modify the exterior of the lights.

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Anybody have input on post #9?

I like this train of thought, but would that affect performance of the driver in normal use?

I have used the glow paint. They have the one green rated longer than all the others and it lasts a long time. Depends on how thick it is applied and you don't want to put it where you will be touching it much. I have had some that lasts for a few hours. Also depends on the Mfg. The link I gave seems to have or had, good stuff. I haven't bought in a while now.

I think if you want longevity, I would try tritium vials. The small ones are almost cheap enough to buy and it's not hard to install, if you can drill a place for them, that allows them to be seen. Other than that, the paint is about the next best thing as far as I know.

This reminds me of those cheap Costco aluminum lights with their XPE emitters (now XPG) that come in packs of 3.

They come with translucent tailcaps and have red LED low battery indicators in the tailcap.

I guess 2ma of loss. I don't think it would mess with mode switching or anything, but I'm just an amateur. I'd wait for a real electronic savvy member weigh it.

Makes sense, but I wouldn’t know which resistor to use.
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That’s the problem, other than a few heavyweights, I don’t know who to listen to on these questions…

^ There are calculators online where you put in the various parameters.

I just realized you would need a limiting resistor in series with the LED like in your diagram. If not, when the driver turns, the LED will be allowed to draw all the current it could take.

EDIT: Here is a calculator.

Where would the positive side of the led actually receive positive? The body would be negative whenever the switch is on and dead whenever the switch is off? It’s still DC and still has to have positive and negative for the circuit right? The circuit, with the switch on, is the driver/led circuit, not in the body. With the switch off, there would not be one. At least I would believe so.

Right. I misunderstood your first statement.

So I would just need to add a resistor on the driver bridging Pos and Neg, and another one on the switch PCB maybe?

I may have an improper understanding of this, but…

The current has to flow in a complete circuit, which includes the tailcap. The current doesn’t just flow to the driver, but through it as well. Normally the current would flow through the switch when it is on, but this would be a bypass for the switch so that the circuit is always complete by going throught the limiting resistor and led.

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I figure if I can keep the amp draw down to 2ma, it would take 40days to completely drain a 2000ma battery, and I can always partially unscrew the tail to lockout/disable the “locator” led

^ Correct. The body of the light is much more connected to positive (via the driver circuits) then it is to negative when the tail cap switch is off.