Switching between LED's

rfarkash

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Jan 12, 2007
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Please forgive my ignorance. I'm building up a 2 cree headlight powered by battery and bflex driver. I'm trying to figure out the simplest way to be able to switch between 1 light on or both lights on.
I assume the bflex can handle this provided the battery voltage is vf+1.

Is a DPST switch the easiest way to do this or is there some other way using the bflex?

I'm just starting out making these lights and don't ahave a lot of electrical experience, so want to make sure I don't do anything stupid.
Thanks
Ron
 

ken2400

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Joined
Oct 30, 2006
Messages
227
I am thinking two simple switchs? Either slide or pushbutton. The some places to buy are

[size=-1]www.digikey.com
[/size][size=-1]www.mouser.com
www.ebay.com

Keep us posted on your final design.
Thanks
[/size]
rfarkash said:
Please forgive my ignorance. I'm building up a 2 cree headlight powered by battery and bflex driver. I'm trying to figure out the simplest way to be able to switch between 1 light on or both lights on.
I assume the bflex can handle this provided the battery voltage is vf+1.

Is a DPST switch the easiest way to do this or is there some other way using the bflex?

I'm just starting out making these lights and don't ahave a lot of electrical experience, so want to make sure I don't do anything stupid.
Thanks
Ron
 

chris_m

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Joined
Oct 25, 2006
Messages
383
Location
England
The easiest thing to do is to have the LEDs in series as standard and use a SPST switch to short out one of the LEDs (ie the switch is in parallel with the LED). I'm assuming here that you're using the bFlex to switch on and off, and so not trying to run the LED switching and the on/off from a single switch.

Of course the question then is why bother if you've got a bFlex? Since LEDs are more efficient at lower current (and the driver is more efficient when the output voltage is nearer the input voltage), you'll get more light for the same power input by keeping both on and using a dimmer setting on the bFlex.
 

Y-Wrench

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Jan 7, 2007
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Out There, IL
chris_m said:
The easiest thing to do is to have the LEDs in series as standard and use a SPST switch to short out one of the LEDs (ie the switch is in parallel with the LED). I'm assuming here that you're using the bFlex to switch on and off, and so not trying to run the LED switching and the on/off from a single switch.

Of course the question then is why bother if you've got a bFlex? Since LEDs are more efficient at lower current (and the driver is more efficient when the output voltage is nearer the input voltage), you'll get more light for the same power input by keeping both on and using a dimmer setting on the bFlex.

I'd have to agree with this as well. Also, you do risk blowing up your bflex or led's if switching with the led's on. All in all, the adjuments available should be more than enough. :)
 

rfarkash

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Joined
Jan 12, 2007
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Thanks for the replies. Good point about blowing up the bflex - hadn't thought of that.
In hindsite, using 2 stars at a lower current would make more sense. I've actually decided to go with only 1 star and drive it harder if I need a burst of light. This is going to be for running at night, so I figure the 120 or so lumens I get a 750ma should be overkill most of the time.
Thanks again - I'll let everyone know how it turns out.
Ron
 

zgurl

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Jan 4, 2007
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Lyon, France
rfarkash said:
Thanks for the replies. Good point about blowing up the bflex - hadn't thought of that.
In hindsite, using 2 stars at a lower current would make more sense. I've actually decided to go with only 1 star and drive it harder if I need a burst of light. This is going to be for running at night, so I figure the 120 or so lumens I get a 750ma should be overkill most of the time.
Thanks again - I'll let everyone know how it turns out.
Ron

Funny enough: I had the same question in another thread for biking lights... and the answer was the same: dim the two leds instead on shutting off one of them! Running, biking... all about the same as long as it is in nature.

:wave: enjoy your light!

PS: as for running, I modded a PT Eos with a cree and IMS17 (see here), fairly easy and really great light!

PPS: Hey guys I have just became enlightened :)
 

Jopi

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Joined
Feb 11, 2007
Messages
6
rfarkash said:
Thanks for the replies. Good point about blowing up the bflex - hadn't thought of that.
In hindsite, using 2 stars at a lower current would make more sense. I've actually decided to go with only 1 star and drive it harder if I need a burst of light. This is going to be for running at night, so I figure the 120 or so lumens I get a 750ma should be overkill most of the time.
Thanks again - I'll let everyone know how it turns out.
Ron

Few weeks ago I finished building three headlamps, one of them is T-bin LuxIII driven with BFlex which I use also for running on paths. For power I use 18650 2S1P battery pack, and for optics I use Fraen medium. In my opinion it´s really great headlamp, light and powerful enough. Now waiting for Seoul P4 stars to come available :)
 

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