Ah, great idea to push the driver out through the switch hole... I finally got it out! Thanks, Serifus :)
Now I have plans... ^_^
DrJomes, you know more about chip programming than most of us.
Eagerly waiting for to your magic! :bigsmile:
There are 3 SOT-23-6 Buck drivers + external FET.
PIC/AVR send PWM signals though 10K resistors.
Good luck with the micro controller Dr Jones. Also it seems ive finaly found my self some time to do some sketching around in Eagle. if this all works out the way I hope it does, I’m probably only going to be getting more kings in the future.
the problem is connectivity between the circuit board and the led
If I apply power to the corner of the led it works
I would be tempted to get 3 xm-l u2’s on 16mm stars, ditch that one and keep the two functional ones for other projects…. 0:) J)
You should be able to resolder the connection or solder on a wire.
I saw on another post that with U2, initial output was higher, but then it decreased… maybe those U2 had flat PCB, copper PCB is the way to go in that case.
I’m going with 3 cheap U2 ones from dinodirect, just got to wait for them to arrive now…
I found this on google
That definitely looks like it could lead to something interesting.
Except as far as i can tell, it doesn’t match up to, what i assume is the PIC.
so the MCU isnt a known unit?
if someone drew out the actual circuit on a king, you could mount a attiny upside down on the board (pins sticking up) and use small external wires to solder to the correct pads on the board and then write custom controls for it fairly easily.
with those inductors on the board sticking up high, you have height for some creative wiring of a attiny in there.
Brian
The MCU seems to be one of these unknown Chinese MCUs with PIC layout, but I haven’t yet heard of anyone being able to reprogram these.
Removing it and put an ATtiny there with “some creative wiring” was exactly my plan 
I also have some creative ideas for the UI, too
with enough room for mod, by replacing stock MCU with ATtiny, its easy to mod King as you wish
And it doesn’t need 3 separate PWM outputs. one PWM can handle 3 Drivers without any problem.
unfortunately I have no king 
more useful modes
temperature control
battery monitoring
It would definitely be nice to have a circuit diagram, wiring in an ATtiny is something i would be willing to do for the sake of custom modes.
While mucking around in the driver, replace those LM358 op-amps in the current sense circuit with something like a LT1466 micro-power op amp… they draw about 1/10 the power and should cut the parasitic battery drain way down.
ATTiny13A with Power down mode when off + port pin to control power to OpAmps via tiny P-channel FET will reduce parasitic drain.
ATTiny can be wake up from external interrupt (button)
Anyone already identified the MCU ? it has no any markings. looks like chinese MCU
I don’t really have SMD soldering equipment, just a normal soldering iron with a 1mm round soldering tip, so I’ll just replace the MCU and leave the rest as is.
I made a 1st version of the new firmware (“kingdrv”) with just the basic UI. It distinguishes between short taps (“S”, <0.2s), long taps (“L”, 0.2s … 0.6s) and hold (“H”, >0.6s). Flashlight operation is based on tap sequences like for example long-long (“LL”), short-short-short (“SSS”) or just “S” or “L”; sort of Morse-style. Hold does nothing yet but will do ramping later.
There are 2 main mode groups and an extended group. In each group the last used mode is remembered.
The commands implemented so far:
S: on/off
L: next mode (within group)
SL: previous mode (within group)
SS: switch to other main group or return to main group from extended
LS: go to extended group
There are some commands that directly lead to extra modes:
LL: high
SSS:strobe
SSL:beacon
SSSSS: momentary mode; exit by SSSSSS
From those extra modes (except momentary) L,SL,SS return to the last used main mode.
This is how far it works on my test board currently; I have yet to solder the MCU to the King and test it there.
Planned are Ramping, battery monitoring, temperature monitoring, some more fancy/fun modes (I’ll add some “secret” modes, too)