Searching for 23mm driver

Hi,
I am searching for a new driver for a noname chinese diving light (old driver is dead).
The flashlight has a 23mm driver and a magnetic slide switch.
It has 3xcree emitters and is powered by 2x18650 batteries.

I did not found any drivers with hall effect sensor built in.
But, would it be possible to add a hall effect sensor to a normal driver?
I have some S49E sensors that I could use - it has about 2,5v output when close to magnet.
Is there any (cheap) driver that can do it?

I could make my own driver also.
I have some ATtiny85-s laying around and a programming tool.
So I guess all I need is a constant current driver. Then I could read the hall sensor and use the PWM to change the brightness? Is that correct?

Can you reccomend a chematic for constant current driver that accepts two lithium cells in series?
I need about 2-3 amps current.

I have not come across a 23mm driver, but there are 20mm ones. Alternatively you could use a partition board or build something like it. Finally, there are also a multitude of rings or adapters you could solder to a smaller driver.

It will take some effort but I am sure you will be successful.

re: hall sensor/magnetic switch; I am not capable of answering that one, sorry. But if the existing switch works you could adapt it to a driver that takes electronic switches, I assume?

lck-led has a 23.5mm driver:

not sure if it would work with the extra 0.5mm diameter?

Were you the one that asked about this in a different thread?

I don’t know about the sensor though…

MTN electronics has a 22 mm FET multimode driver I used to modify my TX25C2, might fit in there if you use a little extra soldering.

Today, when I woke up I got an idea.
What if I use some existing driver that is based on ATtiny - maybe there is unused adc inputs.
I could then connect my hall sensor to this pin and reprogram the mcu with my own custom code.

But what kind of driver I should look? What would be most efficient way to dim those LEDs?
Constant current or PWM?
And if using 3 x cree XP-L emitters in series and 2 x 18650 in series, should I look for driver that boosts the voltage up?