It doesn’t. In some light the springs touch the cell’s terminals even before the tailcap touches the tube.
Yes you can’t have mechanical lock out with non anodized threads, or brass/titane/copper lights.
Yes, I get that with some flashlights there’s contact at the very start of thread screw engagement. Eyeballing it with two of my lights, I thought there was enough of a gap. In principle then, is it very common practice for the contact engagement to start very early?
Yes…depends on the light, though (overall length, spring length, etc).
So…the energy “exits” the negative end of the battery and goes into the spring/switch. It passes the switch and enters into the metal of the flashlight body, traveling through the body up to the ground connection on the driver.
Anodizing serves as an isolator so that current (at normal levels) can’t pass through it. Just like it was paper or plastic or some other thing that doesn’t conduct electricity…but in this case it’s the magic of chemistry that deposits a layer of non-conductive stuff on (and actually in…) the metal.
So the battery is isolated from the inside of the tube by its plastic wrapper…and the insides of tubes are usually anodized as well. The current can only escape through the battery’s + and - terminals.
So…why doesn’t the current pass up through the host metal to the driver when the tailcap is unscrewed a little? That anodizing again. Look carefully at the ends of both the tube and the tailcap. You should see bare exposed metal on the flat surfaces where the two meet and touch when the cap is tightened. The threads on one or both are anodized. So the only place the electricity has to flow is “through” the tailcap metal and into the tube metal through that small flat bare-metal contact point.
If the threads on both cap and tube were not anodized, then the electricity could flow any time, wherever the path of least resistance may be. So unscrewing the cap in that case does break that flat contact area but since the threads are bare, juice still flows. Anodizing prevents that bare metal-to-metal contact on the threads, so the only place left is that flat contact area. And when you unscrew to make a gap….juice can’t go anywhere.
Not all lights are like this of course (beyond just the presence of anodizing), but this is the norm. Some ultra cheap lights don’t work like this and then some complicated lights like the “signal tube” design of the FW3A and Noctigon/Emisar lights don’t work that way either. And some lights can be locked out via the head threads, but some can’t (basically the same reason usually).
I don’t know if this link will be of any help since I think you get the basics already, but scroll to the third graphic…a light that says “battery” and shows the flow of juice. Doesn’t show all the stuff you just asked about but just in case: Deconstructing a flashlight | Deepak Kandepet
The exception is: Emisar has the tail spring on a PCB so the batt-neg is not electrically connected to the cap material, the battery tube screws against the PCB to connect with the batt-neg. In this set-up mechanical lock-out by unscrewing the tail cap works for all body materials and anodisation state.
Ah indeed I didn’t notice there was no contact between batt- and the tailcap, that’s a good solution.
I have no working knowledge of electrical components but have flashed an Emisar D4 once. That being said, why can’t we just flash all drivers to our liking? I know that a MCU has limited capacity but surely there are some firmware(?) out there that will fit. I don’t know how standardized MCUs are though with regards to pinouts if that’s the issue.
How do you know if the MCU is flash-able anyway?
For the most part we only work with the ATTiny MCUs. They aren’t that common anymore, except with manufacturers that use them specifically to support our firmwares.
In addition to being able to identify and work with other MCUs, we’d have to know how the circuits are controlled by those MCUs - though that can likely be “probed” out by someone with enough expertise
I see… sad to hear that. Would you have any idea where to start learning for that? Most UIs are fine with me just want to tweak it a little. Like the SP10S UI is fine with me just wished the moonlight came first.
For me, learning how to tweak firmware on drivers based on different MCUs is too big of a task. Also, some MCU’s can be locked after firmware flashing so they can not be read or flashed again without going through a lot of hassle, and then you have a some manufacturers that have identification markings on the components scraped off so it’s even harder to figure them out.
It’s much easier to design drivers specifically for lights that I like and use my own firmware for them all. Sure, learning how to design drivers and write firmware takes a lot of time, but once you’re up and running it’s easy to change driver board design to match a light you like rather than figuring out how to hack it to your liking. Some examples: I have a 17mm boost driver and I wanted to use that driver in a Convoy L4 which has a larger diameter and a momentary switch on it. All I had to do was to scale up the driver diameter and add the switch: What did you mod today? - #10885 by Mike_C
Another example, I wanted to run my own firmware in a headlight so I made a board design specifically for it: Project Gemini: Yet another headlamp mod. Not a cheapo this time though.
And here I made one for the ZY-T08: Mod/Driver: ZY-T08 series conversion, MT-G2.
I see, Thanks for the insight… So from an expert’s perspective it’s not worth it then? I guess it is easier to work with something you are familiar with. After a few years in this forum the most I can do is still just swapping LEDs.
I can only speak for myself but as I’m not an expert it’s just so much easier to make my own. I started my driver and firmware development here on BLF without previous knowledge of it before, all with the help of tutorials, the wealth of knowledge and people here that where willing to help. The topic of reading firmware from other MCU types and then debugging them for changes is not something that I’ve seen done here, I think for the same reasons as I stated above… But I don’t really know, I’ve never actually tried it, maybe it’s not as hard as I think but now I’m too far down the rabbit hole of making my own to bother.
I really need to learn how to make PCBs. I’d be fine using the same circuits others develop, but if I could adapt them to a PCB suitable to the particular host I want, that would be the dream.
I would want to learn that, too. First thing I would do is to shrink a MT09R/GT4 driver from 46mm to 30mm.
It’s a good time to try kicad, they released the 6th version recently and it has nice improvements over 5.
Have anyone taken apart the dual channel D4V2? What’s the difference besides the driver and PCB?
I think those are only differences.
Does anyone know the copper plate thickness of the FC11 and FC12?
I asked Hank for dual channel driver and copper board because I was going to reflow emitters anyway. He said it’s too different. I wonder what else was changed.
At least my single channel and dual channel KR4’s seem identical. I have also bought dual channel driver and 2 channel pcb from him separately for my projects, so I don’t know why he didn’t sell them to you.