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lasers with high/low settings?

ixfd64

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Some time ago, I saw that SureFire made flashlights with high/low settings. It would be pretty cool if there were lasers with this feature, such as being able to switch between 5 and 500 mW! People could use them for presentations or for satisfying their inner pyromaniac! Are there any companies that make lasers with high/low settings?
 

J

jangles

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I just ordered my first laser, it's an optotronics RPL165 with 9 adjustable settings, hopefully it should be here tomorrow! I'll post some beam shots when I get er fired up... ;)
 

jamilm9

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the driver has 2 paths to the diode.On way it goes through a resistor making it low powered.Other way is a switch without a resistor.
 
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Sure, with an LM317 driver, just have it rigged such that moving a switch changes the sense resistor value. Like have 2 different resistor paths, one of them on a switch. With the switch "open", the resistance is just whatever resistor you have on the other leg. When you close the switch, the resistance will then be the combination of those 2 resistors in parallel.

I'm sure you can devise more complicated systems as well to get exact values for what you want.
 

Benm

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You can build a variable current source obviously.

But getting something like a 5/200 mW switch will prove extremely difficult that way. For a 200 mW diode, 5 mW is barely above the threshold current, and that current depends on temperature as well.

Making something like a ~100/~200 mW switch is quite feasible though, so you can choose long diode life versus maximum power depending on what you are doing.
 
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Example of above: 33ohm resistor always in place, 22ohm resistor in parallel on a switch. Switch off, you get 38 mA. Switch on, both resistors in parallel, you get 13.2 ohms of resistance, which would be about 95mA of current. These would be good values for a Blu-Ray pointer. you could do some similar math to find good values for red diodes as well. And again, this is just a simple scheme for one simple driver.
 
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Okay, so this would require building a separate driver. I'll think about doing that for my next laser project.

-Mark
 
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Benm said:
It automatically wires electrolytic capacitors in kaboom-configuration too? ;)
That's only if you use low-omh resistors.

It looks better than my schematics - most of the time I just draw them on my tablet pc!
 

Xplorer877

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Well the EC will have be able to handle the voltage. Its the same as if you had a pot. Only there is only two settings as opposed to many.

Edit: I just noticed it too.
 




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