Lighted tail switches on a C2+ w/ Biscotti

I recently purchased a couple of lighted switches for my C2+. It’s an 8x7135 model w/ Biscotti firmware. After installing I realized they are not compatible, I’m assuming because the switch leaks enough current through the ATtiny to make it freak out.

Is there a solution to this? Is there a certain resistance value that will let the driver power off completely?


What I recall (checked a biscotti driver for a lighted switch two years ago) is that I never got a biscotti driver working properly with a lighted switch installed, whatever the bleeder resistor value at the driver was, or the resistor values before the leds in the tail.

It will work but, you have to set it in whatever mode set you want before installing the lighted switch. Oh yeah, bonus aggravation, it becomes next mode memory as long as the lighted tail switch is installed. :smiley:

I didn’t have the patience to mess with it so I just abandoned the lighted switch. I have one light that I just used the clear boot and filled it with 4 trits. Not super bright but easy to find on the nightstand in the dark.

Well that’s a bummer. Interestingly, one of the switches causes the light to almost always start in config mode, the other switch will start the light on it’s lowest setting, but after clicking off and on it won’t start at all.

Same resistor values on both, but one is orange and one is blue. I wonder if the difference is in the resistance of the LEDs themselves causing different behavior.

That’s strange, I would have expected a simple bleeder resistor on the driver to solve any weird behavior.

I use lighted tailcaps all the time in my lights, usually with a nanjg105c driver (similar to what most Convoys have). I just stretch a 750 or 840 Ohm resistor between the first star (technically just a ground pad) and the spring. And for firmware, I use my own which has it’s roots in Biscotti… they should act the same in this regard.

Pic here: D.I.Y. Illuminated tailcap - #1748 by gchart

If your driver is the style without stars, you just need to place the bleeder somewhere between ground and positive. Perhaps by stacking on top of the decoupling capacitor.

Just for grins I put a few different lighted switches in one of the Biscotti lights I have left without a metal switch, while I was watching the OU game. I didn’t get all the switches from the same place but the reaction of the light itself is different depending on what switch I have in there. Some orange ones I got from somewhere I can’t remember would only let the light turn on in high. The orange light itself was fairly bright for a minute or two then would go very dim and wouldn’t allow the light to come on at all. Strange little guys.

The trits in the clear boot and normal switch works okay for what I am using it for. Nightstand duty. Maybe I will one day mess with a bleeder resistor for it. I have a box full of “I’ll get to it one day” lights that I really need to get to work on.

That’s exactly what my orange switch does. We must have the same one.

gchart, thanks for the tips. I’m waiting for some parts to come in, but I plan to flash this light with a customized firmware. I’ll try to add a resistor while I have it apart.

I’ll add… I use the “ring board” (Generation 2) style, seen here. Those use higher resistors, and as such, there’s less current flowing when you use those as opposed to the drop-in style that have the LEDs mounted on the board with the switch.

i know this is an older post but ive been fiddling with the lighted tail, how much does the bleed resistor drain the battery? im wanting to use this in an 18350 light.

The bleeder itself doesn’t add drain except when the light is turned on.
The standby drain depends mostly on the resistors in the tailcap (they’re usually much higher resistance).

If your tailcap has a single 15,000 Ohm resistor, that should be around 0.1 mA of drain on a full battery. With a 1000 mAh 18350 battery, that’s roughly 14 months til dead. Those are approximations but I hope they help.

ok thanks. not sure what the resistor values are i didnt look. it is a convoy brand lighted tail switch.

i just looked and it has a resistor for each led and the values on the resistors are 301 so no where near 15k ohms.

Yeah… That’d probably draw closer to 4 mA. Not really a good fit for 18350 unless you closely watch your battery level and recharge it every few weeks.

i usually do charge them every week or 2 but i may try to change the resistors. its really hard for me to change smd components, i shake bad and my eye sight is getting worse.