Very interested and subscribed. There’s a void in the flashlight world which this fills. And being a tailcap mod you can change switch systems quickly if you want to without disturbing the mount or light, Agreed on a cell-holder if not using a Cap, it could be a screwed down strap for absolute reliability while making cell changes easy. Screwdrivers in weapons kit now but don’t want to add soldering equipment to it! Simplicity wins for me.
Phil
The gland will be a key part.
Agreed, maybe this thread will spur someone to come up with a board. A battery holder mounted on the PCB, like a keyless entry fob, would be really nice. Would make changing the battery (yearly/bi-yearly) for added piece of mind a simple task.
Maybe Richard could stock a build-it-yourself kit like some drivers.
It wouldn’t be too difficult to make a battery carrier from a small piece of metal and solder it to the board. I’m gonna see what I can come up with this week. I wonder if there are any rechargeables in the form factor to fit the cavity.
Can you measure the diameter of the cavity? I’m guessing around 15mm.
The diameter of the threaded portion where the retaining screw fits is 18mm. It’s about 8mm deep when the board is fully seated. The opening for the switch boot is just a hair under 16mm.
What about a circuit like this ?
Using a zener to limit voltage to 3v to a small coin battery, like this . Could it be this simple? Or am I just way out of my league on this one?
This is exactly what I would like but in a form of remote pressure switch so I will be watching this thread with great interest.
I ordered this about a month ago to test this mosfet idea.
The higher the gate voltage the lower the on resistance will be, probably not a huge concern at 3A or less but as the button cells deplete that resistance will rise dramatically so a 3 cell or 4.5v approach might be a good idea. Anyone consider pulling the tape switch from a side switched light and getting power for the fet from there?
Or maybe a threaded module that fits between the head and battery tube and contains the fet on a board with the tape switch wires soldered in. That would allow the stock switch to remain as a lock out.
Why don’t we start simple and leave 3 coin setup and threaded modules for later!
This. I’m just thinking a high power remote momentary switch. Because most remote switches have such tiny wires, it kinda kills the amps the driver can get for maximum power!
Amen!
Attempting higher current also kills cheap switches. This device solves both problems at once. Simplicity usually = reliability and can be amended later once the concept becomes proven. One step at a time, let’s start simple (and as cheap as possible without risking reliability).
Phil
I had before this came about, simply because I’m an EE dropout and didn’t get far enough for the whole of this to make sense to me lol.
What interested me was the multi-modes available on some of the side switched lights. And by multi-modes I don’t mean simply multiple levels, but the ability to long press for momentary or double tap for on, or something similar.
The problem I ran I ran into was the drivers I found separately didnt have the modes I wanted, and were all too large to be useful in that application.
Hopefully something materializes out of this that will work for multiple applications.
ETA: On that note, maybe something is already available that will work in a similar way as described above and I’ve missed it. What the smallest BLF driver that is programmable? 17mm? Is one of those be designed in a way that requires constant battery input and the PIC is operated by a separate channel? If so, I’d imagine there is a way to shoehorn one into a light and have the switched signal come from a tape switch. Then a custom program could be made with the operation similar to what I described above.
If this it too far OT guys let me know, I could always start a separate thread it this to keep from cluttering this thread?
Thanks
Smallest attiny FET driver is 10mm.
Mosfet remote tail cap switch.
Been there, done that and have the T-Shirt.
I made these awhile back and they were for positive ground as PT54 as all other PT emitters. My tailcap either switch or tape activated were powered by a CR2016 coin cell. My PT120 thd fet was installed inside of the heatsink so I could access the negative pole and the coin cell was not needed. You can search CPF for a switch called a “FETtie”. I too am electronicly challenged but was able to reverse engineer his design into a spring loaded switch circuit board with a PETE plastic housing and a hot glue gun. For conventional negative ground switch a reverse mosfet from what I used maybe needed. More info is in a post on exact mosfet used.
Mentioned here
Sorry, should have been more clear. What’s the smallest driver with constant battery input that is switched by momentary?
I thought the 10mm was a standard, not side switched?
Thanks
The mtn10DD is available in that arrangement. E-switched, powered are all times(unless a lock out is used). I’m not saying it’s the best option or a budget one but it is what you asked for. Personally I think a driver adds more complexity than is called for, a simple fet with enough voltage to fully open the gate and a pull down to shut it off quickly. Whether in the form of super caps or coin cells should probably be determined by size and space available.
Here’s an lir2032 with tabs. It has a higher nominal voltage than one 3V cell or two 1.5V cells so it should do a better job of holding the gate of the FET open than a cell(s) with a nominal 2.5V which is right on the borderline of the dreaded linear region for even good FETs.
Thanks for the reply.
I agree on all points, just thought a driver like that might work for me in the meantime until something materializes here.
Thanks