Hhmm. No rush - I ordered the 15mm boards, very cheap, so if you get a chance to try it out this weekend and post, that would be great. Probably wil be a couple of weeks before I can get to them anyway. I got a UniqueFire G10 and a Romison RC-29 which are nice quality little 14500 lights which will really benefit from a programmable driver like this. The G10 has a single mode driver with a XP-G2 in it, and the RC-29 is totally stock with the next mode memory PIA thing. I got some other 14500 15mm lights as well.
I have some of the 17s but haven't built one yet. No 15s here, don't really have a use for them.
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So I tried this, didn't have any effect-
(http://edn.com/design/components-and-packaging/4364020/Reduce-acoustic-noise-from-capacitors)
So noise is not from the little cap. It's not caused by the inductor, either (still makes noise with the inductor removed completely, and the pads jumpered), though the inductor used can have an effect on the noise. So far, the quietest one is the .58uH Panasonic...
It doesn't drop the low mode as low as the .8/1.0/1.2uH parts, but you can always drop your PWM values all the way down to '1', and it's pretty damn low. Lower inductance also means it has less of an effect on the higher modes (less DC resistance).
Are there any other options for PWM frequency with the attiny13? Like, lower, where it might be outside the resonant frequency of the parts on the board?
You could try 2.4kHz, which requires changing F_CPU in the source code to 9600000 and a low fuse of 6a. Or you could leave the low fuse and F_CPU as-is but set it to Fast-PWM with a prescale of 8, which would get you around 2.2kHz, or increase the CPU speed to make it even faster (if I have all of that right).
* define F_CPU 4800000 CPU: 4.8MHz PWM: 9.4kHz ####### use low fuse: 0x75 #######
* /8 PWM: 1.176kHz ####### use low fuse: 0x65 #######
* define F_CPU 9600000 CPU: 9.6MHz PWM: 19kHz ####### use low fuse: 0x7a #######
* /8 PWM: 2.4kHz ####### use low fuse: 0x6a #######OK, so why is STAR 1.0 silent (just now tried it for the first time (no changes other than sticking in my favorite levels, 0,2,6,18,54,130,255), using same 0x75/0xff as before), but minimo is noisy as hell? I don't understand the code well enough to translate between the different versions to pick out which difference causes the different behavior...
STAR uses Fast-PWM at 18.75 kHz and MiniMo uses Phase-Correct at 9.4 kHz (just like Luxdrv and BLF-VLD). That 9.4 kHz seems to make every setup whine, and Fast-PWM makes it silent. But I thought the FET setup didn't work with Fast-PWM? Or did your hardware changes now allow it to work?
I don't know, I just took the original STAR v1.0, plugged in my PWM levels, flashed it using 0x75/0xff, and it works.
.txt file of what I pasted into Atmel Studio: http://75.65.123.78/blf-srk/t1.txt
This is weird because I've been using luxdrv with phase-correct at 9.4 kHz for over a year and can't seem to hear a whine in PWM modes at all, on all my builds - lots. Am I just not sensitive to it? Of course at my age, I can't smell much or taste much either - I have to smother my meals in Habernero sauce so I can taste something at least, though it may be somewhat painful... 
Got my 1,000 lumens EDC strapped to my head and drug store #3 glasses on just to get something done on the bench... It's fun, Just you guys wait and see...
My clicky switch/luxdrv lights whine from the switch (the little contacts inside wiggle around), lightly pressing on the switch changes the pitch/volume. Obviously that's not where the noise comes from on the momentary lights though.
Great thread Rufusbduck!
About whining drivers and FETs. Its the main reason why im still on the sideline and seeing all the progress being made by knowledgeable people... I hope you guys finds the solution. I prefer my lights to not sound like there is something wrong with them..
Keep up the good work everyone!
Talking to the EE's at work, they said the magic # is 20 kHz or higher - out of the human range.
Or lower, too. Lower frequency will be less likely to make parts this size move in a way that makes audible noise. Like if you take a poly done tweeter and send it a 200hz signal, it will move but not enough to make a noise you can hear.
The fast PWM in STAR works well with the K4212... I accidentally did that when I was testing the momentary at first. Forgot to switch it...the low modes just weren't nearly as low, high modes were the same. Never tried it with the 70N02 but it may just work as well.
The inductor/etc. seems to definitely add a lot of squeal depending on the size and as Comfy has noted, the size of the capacitor. The problem is that a large inductor + large capacitor = not enough room!
I’m about to put my very 1st scratch built driver together. I’ve got the 17mm FET board, V1, and all the components. But now I can’t seem to locate what goes where and in which direction. This is pointed at which resistor is R1, and which direction does the diode go? Is the line on the diode the positive?
For the diode, best to check the datasheet for the specific one you have. They don't all follow the same rules.
Pics or it didn’t happen 
Tom, I'm still young and I need a headlamp strapped on and glasses as well. My hearing is still good though! 
You really don't want to see this ... Can't believe I'm planning on playing softball again this year - first game this Sunday morn. These guys were begg'n me - dunno why, accept maybe for a few laughs as I stumble down to 1st base. Actually my reflex's are still pretty good - been playing ping pong and can still keep up with the quickness. I pitch, so reaction time is extremely important against these roid rage kids and their shaved bats... (ooops, off topic). Well, bats that are high powered and mod'ed -- sounds familiar...
Sure you can… just don’t shower or change your underwear for a couple of weeks. You’ll be smellin’ big time in no time. J)
Welp, my old standby version of luxdrv doesn't work on the 17mm FET board (sometimes a half-press gives two mode changes instead of one, sometimes none at all), even though with the same components on a 105C PCB it works fine. I think I need a nap.