Utorch S1 mini BLF driver

Hey guys, another driver project here. Like my recent SP33 driver this is a 3channel TA based direct replacement driver for the Utorch S1 mini. It’s 1+4x7135+FET with an on board switch.

You’ll notice a few components missing from the standard TA / Del circuit. R1 & R2 are both gone (but voltage is monitored internally so they’re not needed) and C2 was left off cause of space constraints. The board uses the FW3A HW Config.

I’ve tried both and I highly recommend the 1oz Cu / 1.6mm thick FR4 boards for this one (which is the standard option, what comes if you don’t order any special services). The thinner boards have a tendency to get cockeyed in the pill.

Nice job CK, this might bring the S1 mini’s interest level back up. I believe this is the first board I have seen on BLF with the switch on the board. That’s the way almost all my 16340 and 14500 lights are with a momentary switch. This could possible fit several small lights.

Love ya work Ck. :beer:

Thank you guys.

Moderator007, I have a second S1 mini on its way now but, IMO the biggest hurdle they suffered keeping them from being more popular around here is the price fluctuation. I paid $15 for mine but you can turn around the next day and all coupons are dead and the price was jacked up 100% (literally, ~$30). IDK if they’ve just got supply issues with this light or a component of it or what’s going on to cause that…

The board has those ears on it but it’s 15mm in diameter otherwise and you could file the tabs down in seconds, if you run across anything else it’ll fit let me know so I can keep record!

A couple other things to mention; FET is a SOT-23-3. You’ll notice the driver is round but in my actual pics there’s a flat below the switch, filing this isn’t required but it makes putting the pill back in the light and having the switch line up a whole heck of a lot easier. The driver indexes into the pill all nice and perfect but the pill is totally free to rotate in the body tube so getting the switch indexed [blind] with the button is annoying, if you file that flat atleast you can see it.

CK, do you have any Ideas on how to get the switch raised off the board like I did here but still have solder pads.

Would like something a little easier and more professional looking.

Well the easiest thing would be a different switch. They make some that have big metal cage like supports for exactly that (raising the switch off the board). I find them in tool battery packs on the BMS all the time.

That’s what would be the least work but what I would do is make a vertical daughter board like this well I don’t have any pics of the finished driver so you’ll have to use your imagination…

The switch it’s self goes on a small board that interfaces with the slot in this board. Electrical connection and physical support are the same solder points.

Thanks a lot CK!
I love my S1 Mini but the UI ain’t good. I have too many modding parts and too little skills to buy it now, but the availability is very nice. :slight_smile:

Thanks CK!
I have a dead klarus Mi1c and this driver might be a perfect match for it. My only concern is about thickness of the driver with all components. Can someone suggest a good FET for it?

VERY Interesting! Nice work CK, may just have to pick up a few of those…

AO3400A or IRLML2502 are both good choices. They’re both SOT-23-3 package but the IRLML2502 has a further package identifier called “micro-3” and is even smaller. I prefer to use the larger A03400 but you might find building easier with the IRLML2502.

Thank you again. Probably, I’ll order from both to check out which one will be better for me.