Synching with exposure would indeed open interesting opportunities. Higher power, less heat, longer battery life, but also effects like mentioned above. I have also been thinking testing effects like alternating light direction every second frame, light reacting to sound, but keeping the output constant during each exposure etc.
The prototype of dimmable power supply, i.e fast hack of a up converter works nicely.

it is providing adjustable current now. Next attaching a micro controller to it and to see if the current can be controlled fast enough, or if other methods are needed for frame accurate control.

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I especially like this as it accepts any voltage between 4 and 28V. the only limitations are that max input current is 5A, i.e at 4V only 20W is possible and full 120W requires 24V. The other limitation is that it is fully dimmable only below 20V. Pretty ideal for v-lock battery, with that max power is then around 60W, so the cooling should be also ok.
That though mean that 6 of 10W LED would be enough. now it is 12. It feels though that the light output per Watt is not fully linear, so maybe I keep it like this.
BTW, this inverter operates at 500 kHz, so the LED is getting pure DC, no flickering. Some of the inexpensive dimmers use much lower frequencies and could cause problems at very short exposure times like used on high speed camera.
Edit: first test with external control. the good news is the LED reacts very sharply to the simple control, so it is just attaching a micro controller to it and somehow getting the exposure synch from the camera. The bad news is that for eye, the pulsed LED looks just not tolerable at 30 FPS, like a strong strobe. so this will be for higher frame rates and special purpose.
On this video I set the frequency on purpose a bit of (30.6 Hz) , and short duty cycle se we can see the LED getting brighter and the light moving from bottom to up. In real life it is just flashing 30.6 Hz short pulses constantly.
Note the working lights are on so they cause also the flashing.
So next synching it with the video and using proper camera instead of iPhone

Sorry for getting off topic, I will start a new thread for next update.
oh well just this update still, I got it synching to analogue video out, kind of, just a brief hack, but anyway enough to realise something that is very obvious now. The analogue video is generated in camera, and it has its own frame rate. (PAL or NTCS) so it seems with these cameras the only way would be to synch the camera to the LED, I do not have time to look into it now. Just hope the cameras would provide the exposure pulse out, it would make many things so simple.
The LED control is working great, here testing 6000 times per second on off.

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