100mW+ leadlight ...(laser modifiers please read)

ok, i found this from http://www.phalkin.com/sbk/lasers_index.htm

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Now, the serious things. I have read on the forum, that a guy have shorted the center of the pot with the case (the case is the positive pole of the circuit), and obtain 150mW with 500mA ! So I have tryed to short the pot, not directly for beginning, but with a resistor of 5k. I don't see any increase of the brightness, so I tryed with successive values of smaller resistors. I remark that smaller the resistor was, bigger was the brighness of the dot. So I decided to directly connect the pot and the case, just 2-3 pulses for watching what it happens. And it happens that the dot has a big punch of power each time I shorted the pot! WOW! And it's the same if I short the pot for longer time, like 20 seconds.

With pot shorted I measure about 310uA for 10 seconds constant with the LED test, it means 110mW !! You can't look the dot on a white wall at 2 meters for more than 1 second because the green light dazzle you too much!


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basically what he did was connect the pot with the case, making a short circuit. . . and get 110mW output power :shock: :shock:
anyone tried this before ??

Re: 110mW leadlight laserpointer . . .

Yes tried, laser blew after three days of use - too much heat and current. The diode is only rated at 500ma and 650ma is a no. /ubbthreads/images/graemlins/frown.gif

Re: 110mW leadlight laserpointer . . .

cool, and did you actually get over 100mW ??
maybe changing the diode to a 500mW one will solve this problem. .

Re: 110mW leadlight laserpointer . . .

hmmm, possibly, I got, well I didn't have my meter then but I got over 2000mv on the LED test so I would guess high 85-90mw.

Re: 110mW leadlight laserpointer . . .

/ubbthreads/images/graemlins/frown.gif /ubbthreads/images/graemlins/frown.gif /ubbthreads/images/graemlins/frown.gif When it blew I was gutted so much.

Re: 110mW leadlight laserpointer . . .

interesting. . . now i think maybe:
-pot adjustment
-short pot circuit
-resistor swap
-diode replacement (350 or 500mw)
-crystal alignment and replacement
-IR filter replacement

combine the above methods, we should be able to create a stable and long-lifetime laserpointer with an output of >100mW .. . current might be around 500mA but it isn't a problem aslong as no damage is done to the diode and no laser lifetime deduction

again. . .if anyone has the ability to complete these steps and successfully create a stable and long-lifetime laser, pleace contact me. . I will pay for all the new components (IR-filter, Diode. . etc) that are included in this mod. .

Re: 110mW leadlight laserpointer . . .

Ok mate I'll help you narrow the list down:

pot adjustment - done 320ma max
short pot circuit - no good too much power
resistor swap - sounds promising I am looking at the circuit diagram now
diode replacement - www.ifixlasers.com - still researching
crystal alignment - difficult and very small increase if any
ir filter replacement - not necessary

OK will keep posted on what I find.

Re: 110mW leadlight laserpointer . . .

cool, i believe you are one of the most skilled modifiers around. . . i'll keep in contact with you, and see what i can do .. . /ubbthreads/images/graemlins/smile.gif

Re: 110mW leadlight laserpointer . . .

maybe you can buy a new 5mW from some dealers, and ask them to do the crystal alignment and choose one that has good optic lenses and crystals (or a high quality one for arnold). . . then do the further modification. . .i believe that way, you'll have a better and more efficient laser. . . (don't worry about the price. . BUT, i might not be able to pay soon, so maybe just ask around first. . . /ubbthreads/images/graemlins/smile.gif)

Re: 110mW leadlight laserpointer . . .

btw, i believe changing the resistor to a smaller number is very important, this modifier from http://www.phalkin.com/sbk/lasers_index.htm has done the resistor swap. . .
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First test with no IR filter and 30mW, the black electrical tape smoke a little after several seconds. YES! Then I have changed one resistor with a lower value, and the laser was putting 40mW. With that, the electrical tape smokes a little faster.

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maybe you can try contact him on how to change the resistor

he also made a chart:

Base specification
-Current : 205 mA
-Power : 4mW

Potentiometer turned to max
-Current : 320 mA
-Power: ~ 30 mW

Resistor added
-Current : 370 mA
-Power : ~ 40 mW

Short circuit with case
-Current : 570 mA
-Power : ~ 110 mW

Re: 110mW leadlight laserpointer . . .

hey, check this out. . . might help with the resistor swap
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From: http://www.greenlaserforum.rauch.co.uk/phpBB2/viewtopic.php?t=10&postdays=0&postorder=asc&start=30 by LaZrLight
With all resistors being an equal value, the current I, assumed to come from the positive, would divide at into two branch currents: Ia and Ib. Ia would then divide again at the junction between (a) and (d) creating Im , which flows through the meter. The remainder of Ia will become Id and continue along this branch of the circuit. The current Ic is given to be Ib + Im, according to Kirchoff's Law.

So, we only have one resistor to vary, all the others can be fixed. By lowering the value of Ra, we should see an increase in current in Im in proportion (an increase from 0 that is). With a variable resistor we would be able to get the correct ratio to divide by 2.8 through Im There are a couple of variables like the shunt resistance of the meter to consider…. I'll put something together with 3 fixed and one variable resistor and post the results (I'll have to wait till my "interm" greenie arrives in a couple of days so I can test this out)

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some interesting info on short circuiting
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I was playing with my new 27mW leadlight.. the one I said I would't play with.
The hole under the button is really close to the case and while trying to adjust the pot, I shorted the screwdriver to the body and the top of the pot at the same time.



I did it again and there it is.... a steady beam like a lightsaber.... I measured it on the LED meter... it read 420!!! that's 150mW!! Smokes black electrical tape in 1 second flat!

I have had it on and off a dozen times and it still works. Pulls 500mA which is fine for the diode but the MCA should EXPLODE at this power.

I wound it back to a steady (and safer) 70mW at 320ma. Still smokes tape but takes a couple of seconds to get going. This must be the strangest Leadlight ever! This one is a definite "keeper"


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then LaZrLight and Naquadah start talking about changing the MCA to a higher quality one. . .

In conclusion . . changing the resistor, shortening the circuit, changing the MCA, change the diode and good quality optic lenses and crystals can make a good laser with an output >50mW for sure . . .