my POT moding method + alternative to pot moding = :D

On the "POT moding FAQ's" thread.
I find that the answer to the question "Will I ever be able to get my <5mw to burn matches by pot modding it?" which is answered with a resounding "NO!!!!! :tsk:" is only half true. While POT moding alone can almost never get a <5mw laser pointer to burn there is another simple alteration that can be made that often does. I have successfully modified 4 green lasers (2,<5mw pointers and 2,<10mw modules) with a remarkable 0% fatality rate thus far. What I did was I turned the POT to it's absolute limits by turning it up until the laser ceased to function then back down just far enough to turn it back on. After that I took out the collimating lenses which does 2 things 1 it frees up the few mw of power absorbed by the lenses and 2 it leaves the light emitted from the DPSS crystal focused to a point. The end result is a green laser with a beam size <1/4 it's factory design that has a wide divergence. I have also tested removing one or both of the lenses without pot moding with good results. I find that if you're lucky and the alignment is good only removing the inner lens and replacing the outer one gives a better focal point and divergence. In short I've gotten 4 lasers all able to cut electrical tape,barely ignite matches colored black,and light fireworks for just over $7 each.

Got pics?

before + pot mod to maximum.

after (in host with collimating/output coupler lenses removed)

reverse side

shining at camera

shining at card

Removing one of the lenses makes the laser useless as a pointer.
Also, the gain in power would be negligible.

If you are going to "pot mod" a laser, you need to set the current to a safe range for the diode and adjust the power for the best stability.
Cheap greens have tiny crystals that can only handle so much pump power. If you over-saturate the crystals you will likely get an ugly mode, unstable power, or both.

Simply maxing out the current is a good way to overdrive your diode and the crystals which could result in early death. And yes, for $7 who cares, right?
Well, shipping from China is slow, and after so many dead greens, $7 adds up.

If you want to burn with a cheap green laser, just buy a 50mW from LEDshoppe and use a convex lens to focus it.
There is a right way and a wrong way to "pot mod" a laser, and I would not recommend anyone to do this unless they have an LPM and a multimeter.

I have gotten >100mW peak, 75mW average from several cheap 5mW green lasers with crystal re-alignment/replacement, current adjustment, and improving thermal conductivity in the module, but it is more work when done properly than what you described above.

So the answer to the question, "Can I pot mod my laser to make it burn?" is "Yes, but the kind of performance and life time you get depends on how you do it."

I have to admit that the life span of your laser may be significantly decreased if you pot mod the laser. I also should state that I have not yet broken a laser pointer outright by pot moding it even when that was the intent in order to find the maximum limit one of these can be pot moded to. I'm going to post pics and maybe a video of my results soon as I can figure out how. Note LEDshoppe's 50mw costs $24.99 ,Deal Extreme's 50mw costs $14.38 their 50mw module costs $16.43 , Hottest deals ever 50mw costs $11.95 . Though you could buy the others and have a better chance of getting a working hot laser pointer you could buy 3 the Deal Extreme 10mw laser modules at $7.86 for slightly less than one of LED shoppe's 50mw. On top of that you get the learning experience of moding these how you like them. (I like the fact that these modules screw apart so lens mods are easily reversible) I don't pretend to be an expert but moding the deal extreme modules is the lightest on my pocket book for 50mw lasers. The disadvantages are 1 when pot moded to maximum the DX modules get hot, 2 the beam divergence is crap and will stay that way, 3 the beam may be at an angle if the lenses are removed, 4 the dot may be or become scattered, 5 these lasers barely burn no matter what alterations you do , 6 buying from Deal Extreme is in and of itself taking a chance and has no less than 3 weeks processing and shipping time.

In response to the above post it is true that removing the lenses makes the laser useless as a pointer but excellent as a flash light however I find that it does radically increase the close range burning power because the lenses expand the beam about 4X while focusing it to infinity.

The reason the thread you referred to says, "No", is because it encourages people with perhaps less luck than you've had so far to merrily go and try to pot mod a relatively cheap, (or perhaps not), laser and quickly end up with no laser at all. This is not a sensible way to go about getting a burner. The sensible, and in the long run cheapest, way to do it is save up for a decent module and host, and build it yourself.

RA_pierce is correct when he effectively says you need more than just a screwdriver to do this correctly. I bet that behind his personal successes are a number of failures due to the unpredictable nature of these, (Sorry, RA, this is an assumption of course). The experienced members on this site will not endorse this practice because of the risk of giving people information that can lead to a broken laser, amongst other things, and all the recriminations that entails. I would ask you not to put up a video showing this. It not only opens you up personally to the flak from Johnnie Noob demanding you pay for a new laser because four of his broke as a result of the your advice but opens the forum to fielding the questions like, "I was told pot modding is fine. Why is my laser broken? You guys know nothing!", and, "I just tried to pot mod my 200mW laser to get 1W. I've just wasted $300!".

Although it can be done, this technique can be seen as more of a hack than a proper modification. Pot modding is a gamble every time you do it without the correct gear and knowledge and even then it's not gauranteed. You may have won four in a row so far but this is no proof it's safe. By all means go ahead and do this to your own but please don't encourage others to do it.

Cheap 200mW burners in red can be bought for only a few bucks so if you're willing to render a green pointer useless, as a pointer, then just go for one of these reds, (or even a cheap BR), to satisfy that burning urge. Otherwise, just enjoy the green, your beams will be tighter with less divergence than any cheap red burner.

M

Everyone knows that pot moding is unsafe for the continued life of their laser. I'm trying to empathise that removing the lenses in a common <5mw DPSS green laser is an alternative to pot moding which is less harmful than altering the power input. However there is precious little information on how to correctly mod/hack a cheep laser pointer with every attempt being shot down. For the record I am currently trying to find the parts to properly drive and collimate a 445 1W laser diode when I do I'll enjoy it.
Also anyone tampering with their lasers will make mistakes and break a few. It is because of this that my opinion is if anyone has the lack of common sense to be tampering with a $300 laser without the experience needed to keep from breaking it they don't have the common sense to use that kind of laser safely and thus don't need to have one in the first place. I am merely posting my results thus far with my selected "hacking" method and I will post my failures as well when they arise.

Btw what website do you upload your pics through in order to post them ?

I don't mean to discourage you or "shoot down" your findings.
As a matter of fact, I don't like to discourage "pot modding" as it can be a fun way to experiment with lasers and learn a bit about them.
I'm sure every builder on this forum has/had a few cheap greenies that were "pot modded" in their collection.
"Pot modding" green lasers has always been a gateway into the hobby for many, including myself.

psi seeker 34 said:

Everyone knows that pot moding is unsafe for the continued life of their laser. I'm trying to empathise that removing the lenses in a common <5mw DPSS green laser is an alternative to pot moding which is less harmful than altering the power input. However there is precious little information on how to correctly mod/hack a cheep laser pointer with every attempt being shot down. For the record I am currently trying to find the parts to properly drive and collimate a 445 1W laser diode when I do I'll enjoy it.
Also anyone tampering with their lasers will make mistakes and break a few. It is because of this that my opinion is if anyone has the lack of common sense to be tampering with a $300 laser without the experience needed to keep from breaking it they don't have the common sense to use that kind of laser safely and thus don't need to have one in the first place. I am merely posting my results thus far with my selected "hacking" method and I will post my failures as well when they arise.

Btw what website do you upload your pics through in order to post them ?

Click to expand...

Here's the thing.

Most of these cheapy green 5mW modules only have a low powered pump diode to begin with, maybe on the order of 50mW or less. Some may use higher powered pump diodes around 300mW for 50-75mW modules.

Before the manufacturer ships them out, they bin the modules according to output, and chances are that's the most they're capable of.

By pot-modding, you're putting more than the recommended power through the crystals and pump diode.. That will shorten their lifetime drastically, because the components are already maxed out.

Sure, I can drive a red diode via direct drive, but it won't last very long. Same methodology.

Also, I think you removed the wrong lens. If I remove my collimating lens, but leave the output coupler in place, I get a highly divergent beam that quickly spreads out to 12 inches square at three meters.

The only time I've seen an extremely narrow beam was when I also removed the output coupler, and the resulting beam was exteremly divergent. By removing the output coupler, you're also allowing harmful (and dangerous) amounts of 808nm infrared radiation to escape. This infrared can be seen as a deep red dot through safety goggles.

Everything you've said is true. When I said I removed both lenses I meant the collimating lens and the output coupler I just couldn't think of the name of the other one. When both lenses are removed the burning power is increased however if the beam is aligned well enough after removing the output coupler it further helps the divergence and the burning power to put the collimating lens back in place.

I'm sorry, but I don't think, "Everyone knows pot moding {sic} is unsafe... ". Yes, it can be done and is done regularly but the reason it's not 'advertised', is because the outcome cannot be gauranteed and that is not something to post in an open forum like this IMO.

As I said in a previous post, do this all you like with your own lasers but a tutorial on how to do it properly needs to show the ways to measure current draw; optical output; describe the finer points of alignment and how to improve the other things mentioned by RA_pierce. By the sound of it, I don't think you can do that right now and without failures and understanding why they were failures I think you should hold off on your tutorial project. Once you've gained the knowledge, and make it expressly clear that it is a gamble and any mod/hack made at the owners own risk, then it may be argued that a tutorial can be shown publicly.

Mr pierce here seems to have some valuable experience of these things so talk to him and others to build on your knowledge before posting any more on this. He, and they, may disagree with me but that's my position on any planned video tutorial.

You mentioned again that the aim of this is to produce a burner and negate the pointer, as a pointer? Well, research and build a proper burner rather than doing a hack job and teaching others the same poor skills. To do this to just get a burning laser is no better than our, "YouTube Friend". Pot modding, if done, should be to improve the laser you have, not trash it in the way you seem to want to and I think you've missed this point.

Incidentally, @goninandbl00d and psi, are you still seeing any green output when you remove the output coupler?

M

OK no video tutorial until I get more skill in doing it properly.

Also I do still get green light in enough quantity to light fireworks with after removing the output coupler however the beam is sometimes emitted at an angle when compared to it's original output direction even if that angle is just enough to throw off the alignment but not enough to be noticeable otherwise. I would also like to note that the output coupler was nearly touching the DPSS crystal in the ebay pointers and if the crystal itself/it's housing is removed the laser will only emit IR and it's virtually impossible to glue the crystal back in place if it gets accidentally removed. (one of my 4 lasers was broken this way)

I'm glad you are seeing the sense of my point. Thank you.

I would now be very cautious and go and read up on DPSS again as I strongly suspect the lighting of your fireworks is being done by the IR and not the green. This is important to know and understand. You have an IR torch not a burner working by using the 532nm light at all. In fact, to work even better you might as well remove the crystal set entirely and just use the IR, however this is not sensible in the least without suitable eye protection.

These are the dangers that exist with DPSS, (I'm sure you know this bit), but that's another reason to not advertise Pot modDing. It starts with a turn of the pot and due to curiosity ends with huge outputs of IR once you start to dismantle things. If these pointers you have are of the type with a strong ~300-500mW pump diode and you haven't got any goggles, you have been exposing yourself to dangerous amounts of IR, (both 808nm and 1064nm), that's being hidden from view by the apparently much brighter green. If you want proof, and haven't done it already, view the output on a non reflective surface with a CCD camera such as on your phone. If you still do not see the IR, a blueish light on the phone, then remove the crystal set and try again.

Thanks again and I wish you luck with your learning.

M

As a matter of fact I have a pair of Olike brand laser safety glasses designed for 200-450 and 800-2000nm light (this kind specificity) 405nm,445nm,808nm,1064nm safety goggles/200-450,800-2000nm [OLLS1064] - $45.99 : Welcome to O-Like.com, Your source for laser products

I've been meaning to test the power of the diodes in these modules by replacing the internal diode with a 808nm 300mw one in order to see if any noticeable changes occur. From that I should be able to make an educated guess as to the power of these diodes since I don't yet have a LPM. By the way what's the cheapest LPM that's not a piece of junk ?

I wish you luck with replacing the diode and getting alignment correct. You won't be able to make an educated guess at all IMO. What if it's a 500mW diode in your pointer? What if you have damaged it already? You need an LPM to ascertain optical output power, period.

For an LPM I would exercise your searching skills to find one yourself. There's two whole sections to buy things in .

M

Provided that I don't break anything important if the original diode is 500 mw the crystal shouldn't lase as well if at all, if it's less than 300mw it should get brighter or break the crystal, if it's at or near 300mw it shouldn't change much if at all. In short the best I can do is estimate until I invest in a LPM and the purpose isn't to measure power accurately as much as it is to see if there are any noticeable changes.

No, you're wrong. Alignment is critical. You have no way of gauranteeing you have aligned your new diode with the crystal set correctly. There are just too many variables to even get a ball park. Estimating the output of an 808nm diode by how much green you get out of a cheap 5mW laser? You are somewhere... But it ain't this planet. The closest you're going to get for an answer to what rating your original diode was is onion-banana juice.

M