I was thinking of using PWM to switch the MOSFET, and hence the LED, on & off so that by varying the ON time during the cycle, you vary the effective brightness of the LED. By using a short cycle time, say 0.001 sec (1kHz clock) it will not appear to flash and even the shortest of exposure times will be fine (as long as it is over 1/100th of a second or so ).

One downside I can think of is that for a simple PWM generator using a 555, you may have problems at one or both ends of the duty cycle: fully on and/or fully off may not be possible - would need to experiment. This is of course more complicated than using a simple variable current source (a MOSFET and a few resistors) but I suspect it is more efficient as less heat should be dissipated in the MOSFET as it is either completely on or completely off (oh dear... that brings in the 'D' word..!) except for the very short time as it switches from one to t'other.

Anyway, you have something that works and that's the main thing!

Can't help re' the name change: I had a look myself a few weeks ago and could not find a way either. Perhaps Sean can make the necessary changes.


Cheers, Bob.