2 LED circuits in 1 flashlight body?

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juandigital
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2 LED circuits in 1 flashlight body?

Hello,

I’m designing a strobe light for my ultralight and was wondering if it was possible to have both white and red LEDs flashing at different times.

example:

Flash, Flash (white) pause, |+Flash (red) pause+,| Flash Flash (white)| repeat

I could design a MCPCB that would have 2 circuits but how could the LEDs be powered?

Would it need 2 drivers each driving it’s own circuit?

Thanks!

Lightbringer
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That’s incredibly vague, but if you’re designing it from scratch, I’d say yes, anything’s possible.

Being that a strobe would have an extremely low duty-cycle, a single 18650 could power it for a long time.

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juandigital
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I apologize for the vagueness, I’m new to flashlight modding. So having two different drivers would be the only way to accomplish the multi color strobe effect?

FmC
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I think what you need is capable on an existing multi-channel driver, (Fet+1 style) possibly with a couple of tweaks, depending on the output needed.

You would need to customize the firmware, which several folks here could help you with.

Lightbringer
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That’s just it… you said you want it for your ultralight, but are new to “flashlight modding”.

So, are we talking an actual flashlight (mounted like a bike-light??), or a dedicated strobe circuit for the UL?

 

Sure, you can use 2 drivers to regulate current to each LED, and would have to “strobe” the drivers (assuming 1-mode constant-on).

Might just be easier/-est to design the whole thing from scratch. Use one µC to generate the strobe signals, put the current-regulation on-board (parallelled 7135s), and just run short but heavy wires to the individual LEDs.

Or use big honkin’ 1-mode drivers (say, 2.8A, maybe lots more given the low low duty-cycle) for each LED, and break out the enable signals from each, then run just those 2 signal wires to the µC.

For the drivers, any 7135-based drivers (NANJG 105C, 105D, etc.) all you need to do is desolder the µC, or just lift up that one pin that runs to all the on-board 7135s, then the trace going to all the 7135s will be your enable signal. Repeat for the other driver. Use those 2 enables to your µC.

Hell, just use a third driver and reflash that µC to get your strobe signals.

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juandigital
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Thanks Lightbringer! If I use 2 drivers, could I have different strobe modes? Some of the modes would use the 2nd driver, other modes would just use the 1 because not all modes will use both led cicruits.

Lightbringer
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juandigital wrote:
Thanks Lightbringer! If I use 2 drivers, could I have different strobe modes? Some of the modes would use the 2nd driver, other modes would just use the 1 because not all modes will use both led cicruits.

With 1-mode drivers, you could have whatever strobes you want. Enable = on, full-tilt.

The 3rd driver (controller only) would be programmed to strobe whatever pattern you want. Eg, R, W, R, W, RR, WW, RR, WW, R, W, R, W, etc.

Or, if you could live with asynchronous flashing (R/W go at their own independent frequencies), then you can make do with only 2 controllers, by reflashing the µCs on each driver. That’d be the simplest.

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