Thanks guys for all the praise. Hope to see some good mods out there!
Regarding making and selling completed units, some adjustment of the Rsense resistor is required by the user, due to LS variations and the choice of battery chemistry. Proper adjustment requires accurate tools and intricate soldering.
So there's no good way to pre-make the module and then have you connect your own LS and batteries. Even if we supplied the LS (now difficult to obtain), there's still the battery issue---if we set it up for typical NiMH's, and you use alkalines instead, you could burn out your LS.
For that reason, we're generally not interested in selling completed units. However, anyone else is free to use our designs and sell units to others, assuming these issues are properly addressed.
That said, we will have about 15 extra 13x13mm PC boards available, for those who can do the soldering. More info on that, after we work out some details.
Now, to answer some specific questions:
Could this circut be modified to work with other battery combinations?
With a single NiMH cell, it can only provide about 200mA to the LS. Alkalines don't do as well as NiMH's, due to the high input current demanded by the converter. The published circuit is not designed to work with three or more cells, as it's a "boost converter"---the input voltage is lower than the output voltage.
Is the heatsinking good enough?
That's a really good question. Careful filing and use of heatsink compound should provide excellent heat conduction to the case, which I found warms to about 15°C above ambient.
But the sealed nature of the MiniMag provides zero convective cooling on the interior, so the 60°C figure mentioned on another thread is not out of the question. Measuring the actual board temperature while the unit is sealed and operating is, as you can imagine, quite a challenge.
Does this design allow the "swapping" of the ls with the newer (twice as bright) version?
If the new LS has similar power requirements, then I don't see why not. Even better, if it's able to provide the same brightness at half the power, then that goes a long way toward addressing the excess heat issue.
However, if the new LS requires twice the power, then it's doubtful the circuit can provide it, and even more doubtful the excess heat can be sufficiently dissipated by the MiniMag (or most flashlights) without significant case modification.
