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An alternative for controlling 3W leds

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Hi,

probably old news for the experienced Dome users but I've just found a link to a 3W LED mounted on a pcb which only requires power and one control pin.

Rather than using MOSFETs etc etc a dome could be built using only one LED driver board with all the LEDS wired in parallel and a single control wire for each LED

https://www.ebay.co.uk/itm/3W-High-Power-KEYES-LED-Module-With-PCB-Chassis-For-Arduino-STM32-AVR-UK/232870808490?ssPageName=STRK%3AMEBIDX%3AIT&var=532402693460&_trksid=p2057872.m2749.l2649

I've ordered a handful to have a play with

Kev

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The Keyes 3W modules seem to be very optimistic on power rating. They only pull 0.17A at 5.7V so loosely only 1W. Using a Colorchecker calibration and setting a white balance on a grey square they are also running at 8200k.

I also have a box full of Bridgelux 6500k Daylight White 3W star pcb mounted LEDs. The LED board on the KEYES device is only two solder leads onto a star pcb and very simple to remove and replace with a Bridgelux module. The Bridgelux LCD is pulling 0.4A at 5.7v so 2.3W and is approximately one stop brighter and runs with a colour temperature of 6750K.

I suspect the 5.7V value is probably a bit low as I'm using an commercial LED driver to power the LEDS and the voltage waveform is likely to have some ripple on it.

The dome build will continue with the Bridgelux 6500K leds :)

 

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On 9/14/2018 at 3:27 AM, leszekp said:

You might give this site a look (not that I'm biased or anything):

https://hackaday.io/project/11951-affordable-reflectance-transformation-imaging-dome

Your site gave me the inspiration to start my own little project :)

Because my dome will only get used infrequently I've changed the fully automated system you've built to ease my build time. I'm going down the route of a dome with only seven 3W leds inside on a radial line from the bottom to the top of the dome. An arduino will control and synchronise the LEDs and triggering of a Canon 5D4 camera.

The duration of the LEDs will be defined by the camera shutter by sending a signal from the camera back to the arduino so it turns the LED off when the shutter closes and the sequence moves on to the next LED.

Once the first set of seven images are complete I'll manually rotate the dome 'x' degrees and shoot the next sequence. The dome is going to be mounted on a separate base so it is completely separated from the subject and the camera.

Kev

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