Yes, no-FET versions are for single channel lights, like 7135 bank or single constant current regulator. Instead of modifying the driver you can change the hw-config file, of course. Then use a single channel config as a template.
The resolution depends on the MCU (is it 8 bit or 12 bit PWM?) and the curve might need some tweaking to make it look linear. Not sure how thermal regulation behaves on a FET-only light as lower levels are expected to not need thermal regulation AFAIK, but I might be wrong. There are some parameters you can tweak in the config file, but I’d wait for ToyKeeper, who has tested so many different lights and might have a better insight of how to change these parameters.
Getting it to run on a FET-only light probably isn’t difficult, but it’ll depend on the exact hardware, and in particular, there are difficulties at the low end as already noted.
With a tiny1634-based driver, the low end can be improved (lower and smoother), but on a tiny85 there’s little to nothing which can be done, depending on the exact hardware and pinouts.
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If it’s this driver, and if I read the diagram correctly, it looks like it uses an attiny85 and the pin mapping is something like…
pin 5: 1x7135
pin 6: 8x7135
pin 3: FET
The easiest way to run this FET-only would be tell FSM it’s a 3-channel driver, and put zeroes in the ramp tables for channels 1 and 2. I haven’t made the tiny85’s pins reassignable yet, so the FET would be treated as a third channel.
The t85 has a maximum resolution of 8 bits, so the lowest level will be fairly high. It also has the ability to change the “TOP” PWM value, so dynamic PWM is probably possible… but I haven’t done it that way before so it’d need some extra work and experimentation. Or it could potentially be improved by implementing delta-sigma modulation in FSM, but that’s a fairly deep change… and pin 3’s PWM circuit isn’t buffered, so the DSM output would be a little glitchy. It only works cleanly on pins 5 and 6.
Alternately, it could just have coarse resolution for low modes. That’s the easiest solution.
If possible, I’d recommend using the 7135 channels for low modes. It goes lower, is more precise, and is more stable. But if it’s a higher-voltage light, like 2 or 3 or 4 cells in series, the 7135 chips won’t work.
Thanks for your replies, Tom E, SammysHP and Toykeeper.
Anduril or Anduril 2 are both fine. It is the 30mm TA driver that you linked, Toykeeper. I’m planning to use it on a 4 cells in series flashlight. It did work fine with a single 6V XHP70 but it failed with a few XHP70. That is why I’m asking for a FET only version so that I can remove the 7135s from the driver.
A coarse resolution for low modes would not be a problem, it doesn’t need to be too complicated.
for attiny13a firmware. Without having looked at the code I don’t know whether the UI you want is there already, and/or whether it would be difficult to do. Either way, you will need some special hardware to reflash the chip on the driver board.
I’m not sure if that still uses the same firmware or if it’s a newer light with one of LoneOceans’ drivers. If the firmware is recent, you should be able to find out by using the version check function as described here. If it blinks out a product ID, use that. Otherwise, if it doesn’t list a product ID, it’s probably old enough that it uses the firmware you linked.
I recently upgraded the firmware of a Sofirn SP36 BLF LH351D 4000k (old version without powerbank-functionality) to Anduril 2 (and added two 5.1kohm pulldown resistors to the USB-C CC1 and CC2 pins to “ask” USB-PD compliant chargers for 5V using C-C cables). I also changed the button LED colors to red and yellow instead of red and green. The yellow LED’s seem to have a higher Vf than the green LED’s though, so the button LED is now unfortunately only visible on “high”. I tried decreasing the on-board current-limiting LED from 1k to 500ohm but that didn’t really do much… Is is possible to change something in the firmware to increase the lower button-brightness? Thanks!
(I flashed the “anduril.2021-12-13.sofirn-sp36.hex” file btw, and so far I noticed that SOS is missing from the Sofirn SP36 (Pro) & Q8 (Pro) diagram, but I won’t miss that haha)
I see, thanks for the quick response! Could I change the 1k resistor to maybe 100ohm to get a higher “low” brigness? The lowest I went to was 400ohm I think… Although when changing resistors the “output” voltage didn’t seem to change all that much so I doubt that’s going to give the desired effect, I suppose I just need to find yellow/amber LED’s with a lower Vf…
Thanks. I didn’t thought about checking it out before disassembly. A bit strange because the original fw3a has fet+7+1. I know that the new ones have fet+1, but I didnt know that the soft has changed too.