The Uniquefire AA-S1 is a very nice single mode AA light. If you decide you want to convert it into a multimode light you quickly find that it's hard to find an appropriate driver that will fit into the 14.7 mm space.
Fortunately miguelmoreto has already descibed [1] how to easily squeeze a 17 mm board into a Trustfire F20 by removing a brass ring used for making the ground connection. His instrucions work almost perfectly.
The brass ring was pressed in too tightly to be pried out so instead I used a small dremel tool to cut the ring, after which it slid out easily. I am keeping the ring in the event I ever want to revert to the old board.
I chose the NJG-18 for two reasons. First, one of its programmed groups has mode of low-med-high with no disco modes. Second, the output voltage is adjustable. That I thought might be an important feature, in that the Vf of the Osram emitter is 2.4 V and most drivers seem to be designed for the higher Vf of Cree emitters.
The battery current for different settings of the adjustment potentiometer follow.
With the pot set at 1/8 turn ccw (-1 on the graph) the output at 1.00 m is 77 lx, 420 lx and 810 lx. The maximum output is slightly lower compared to what I measured with the original driver, ~950 lx.
Note that with the pot set to 2/8 ccw (-2 on the graph) it refuses to go into high mode.
All in all I'm even happier with the AA-S1 than before. I normally use low mode around the house, which should result in about 18 h battery life. The high mode is just as bright to my eye as before.
All those nasty blink modes are still a trap for the unwary. The 12f629 is asking to be reprogrammed next.
[1] http://sites.google.com/site/miguelmoreto/home-eng/projects
Cheers,
Angus