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ArcticMyst Security by Avery

Variable Power Setting For Drivers?

Glitch

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Aug 23, 2010
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Let us suspend disbelief for a moment, and consider the following proposal:

Is it possible to either run a driver with a variable power setting (rotating head, switch, slider, etc), OR, run two (or more) drivers on the same circuit, set to different power levels, to drive a laser?

In either case, the maximum power level of any driver would have to be equal to, or lower than, the input current required for the laser diode.

For example:

A laser diode requires 3 volts at 200mA (Arbitrary, since I know next to nothing about actual current levels). Couldn't we set the driver's potentiometer (I think that's what it's called) to be adjusted with the head of the laser mechanism, with a minimum of 1mA and a maximum of 200mA? Alternately, there could be a switch, similar to the mechanism which swaps between gas tanks on a truck, which would alternate between a full-power, 200mA driver, and one set to 100mA?

It seems as though it could work; just looking for confirmation.
 





Joined
Jul 17, 2010
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You could build or buy a driver with a click position potentiometer, and using a test load determine the output current for each setting.
 

Cheech

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Mar 29, 2010
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There are many ways to do what you are asking. The Arctic has the smart switch, many high lumen led flashlights have multiple modes like high, mid, low, strobe.
For the lm317 driver you can put an extra switch with a extra resistor paralleled into the resistor line to lower resistance and bump the milliamps.
 
Last edited:
Joined
Jun 12, 2010
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I made the variable power laser (in my sig) using a high quality flexdrive from DR Lava.
I do believe Dr Lava's can be run in parrallel as well.

Even linear drivers (LM317 Based) should be easy to do with selectable resistance paths in the IC adjustment loop.
 

awlego

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Oct 9, 2009
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While my build is nowhere as small as LazyBeam's, I have an adjustable RGV that uses three pots on the outside of a project box to manually adjust the power of each color. I used DDL (LM317) circuits for all 3 lasers.
 

Benm

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Aug 16, 2007
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Yes, its entirely possible, both using one driver with variable current, or using 2 drivers, where you add in the second driver using a switch to go from low to high power mode.

The simplest way is just to build one driver with a adjustable current. You can adjust that while the laser is powered on if you give it some external control (potmeter, slider, whatever).

Adjusting all the way down to zero is not very useful though, you need at least the threshold current to get any light at all - so for a red LOC you'd get some adjustment like 70 to 300 mA.
 




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