DX Green Lasers questions...

I'm thinking of buying a DX (DealExtreme)Green Laser, but I got some questions...

1) Should I buy a 30mw or a 50mw Green Laser beam? Its it true that the 50mw has no IR filter? What about the 30mw? 10mw? 20mw?

2) Should I buy the pen type? I heard that the batteries that power the pen type is much cheaper than cr2. Is this true?

3) I'm planning on ordering it today (June 25th, 2007), when will I receive it? Should I pay for the EMS? Will it arrive earlier?

4) Can I use these Lasers in public at night (obviously pointing it up)? I heard its illegal to use any laser above 5mw, will they really arrest me? lol

5) Which batteries should I use? I have a 5mw Green Laser and the batteries that it was shipped with die already, and I just use it for 2 days.

PS. If DX Lasers are not good (since I heard they don't have IR filters, I may be wrong), can anyone of you offer me a site that sells 5mw-30mw Green Lasers at a affordable price and good quality?

Thanks!

1. I would take the 30mW ... the 50mW is considerably more expensive and the difference between 30mW and 50mW is little, at least for your eye. In dark settings the beam is clearly visible and it should be visibly more powerful than your green one. I´ve read here that the lases 50mW or below should have an IR filter ...

2. The pen type laser use regular and cheap AAA batteries. You can also use lithium primaries and nimh rechargeables too. Lithium primaries should give you the best performance, Nimh are as good as Alkaline batteries IMO, but cheaper. If the small form factor isn´t Nr.1 on your list, I would go with the pen type laser.

3. Only god knows , 2-3 weeks ... EMS maybe faster, but from my experience, the actual shipping time is the least part of the whole process. I ordered recently a flashlight from DX, one that was immediately available. I was happy, when I saw the status "shipped" 24 hours later on their website. But then, it tould f*ckin 8 days until HongKong post had the package in their tracking system and finally 10 days after dx stated "shipped" my package left Hong Kong. Damned yellow .... :whoopin:

4. Depends on your country, if you do something like that in the vicinity of an airport ... yes, they´ll arrest you for sure . I wouldn´t use it in real public situations, maybe alone or with friends but never in a crowd or on a public event. And with friends, I wouldn´t give the laser in other hands, because very few people know about the dangers of these highpowered lasers. They could think it´s same "toy" as the little red laser pointers and some seconds later, someone has lost major parts of his eye sight forever ... not funny, imho .

5. These lasers are sucking a lot of power from the batteries. As stated above, you can use NiMH and also the expensive lithium primaries ... but NEVER LiIon-rechargeables!


I bought a 30mW from DX some months ago and it´s okay for its price. My unit only sometimes reach the 30mW level and I haven´t figured out yet why. It´s not (only) a battery thing, somethings else is working erradic. For comparision, I have a - well performing, I guess - 10mW from Wickedlasers and the DX 30mW can beat it only sometimes. All lasers in these price range are more or less the same ... you won´t find better quality for this price elsewhere, imho.

If you would like to have a "good laser", my guess is you should buy a expensive one from a "real brand". The DX ones are - more or less - cheap quality ... you get what you pay for

do NOT.. i repeat.. do NOT use EMS shipping.

Using EMS shipping will almost GARANTEE your laser of getting confiscated!! many have already explained.

Summary: There are tens of thousands of air mail packages on a plane. DX actually labels the bags as "LED Flashlight Gift". With that vast quantity, customs let it slide and briefly, sometimes not even examining the contents. But on the airplane, there are only a few hundred MAX of EMS packages, and they're kept in bins separate from the rest. Since there are far less in the EMS bins, customs can single out a laser MUCH easier.

Most of the posts in this forum of laser confiscations have happened when the user used EMS shipping.

True, and even DX is warning against using EMS shipping.

On the IR filters - there's another thread on this but - NONE of these pointers have any IR filters, and they openly admit it. At first the verbiage seemed to indicate that the 5mW did have an IR filter, but after reading carefully that one doesn't either.

I think the <$20 5mW one is a good source of replacement 808nm diodes, though. Thanks for reminding me to buy a couple for...harvesting

Hey cool, a thread I can actually contribute to!

First off, I got my DX 50mw about 3 weeks ago, I have never had a green laser before so I cant really compare brightness to other ones but let me tell you, my 50 is BRIGHT, at dusk and late at night outside the beam is amazing!

As for shipping, I did not get the EMS shipping, figured I would just sit it out and wait after reading some of the horror stories of how long it takes to ship, but low and behold, 5 days after I ordered it, it showed up in my mailbox, I live in California so I don't know if that had anything to do with it.


As for pointing it in the sky, prolly a big no no, I do however take mine out to one of the large national parks out here and play around with it every now and then, it's pitch black out there and no one living around for miles, feels like I am weilding a giant lightsaber!

Hope this answers your questions, if you have anymore let me know.

Thanks. Since these pointers doesn't have any IR filters in it, what are the effects of not having any IR filter in the Laser? Will I blind my eyes if I see the dot? or the beam? Will I have to wear special "goggles"?

I'm not sure where everyone is getting the idea that the DX greenies have no IR filter, my DX 30 appears to have a very reasonable one, I couldn't get any decent IR photos using an RM90 filter (yes I know it starts filtering at 900nm but it should let at least some 808nm light through i think). Anyway this is the actual measured IR from another thread quoted for your convenience.

flashlightpoor said:

I finally received my dx laser. I don't think I have read a single post on this forum of someone who measured their laser with an actual laser power meter. There's speculation of the power, the IR, etc. I was so excited!

How much power?
I just finished measuring mine. Using a Coherent power meter I measured 24 mW with the included batteries. With fresh alk. batteries I measured 32mW. After 5-7 seconds the power declined as the batteries were likely sagging.


How much IR?
First I used an ocean optics spectrometer and measured only a single line, centered at 532 nm and about 10 nm at full width half max. There was no IR, but the ocean optics' range ends around a micron, so I wondered if it just wasn't detecting it. I decided to try filters.

First I used a long pass filter and using the power meter found no energy above 700 nm. Next I used a very good bandpass filter centered at 532. I measured the un-filtered power and then the filtered. If there were IR the readings would be different.

What this means is this laser has a very good IR filter. the resolution of the power meter is .1 mW so I can confidentrly say there's no appreciable IR coming out of this laser. Of course yours could be different, different parts, assembly etc.

next I am going to take it apart and build a better power supply so the batteries don't tach out after 5 seconds.

Click to expand...

From my understanding "IR leakage" is only a danger in some situations or setups. The problem with the collimated green laser light ist, that it get focused on your retina and smokes away important parts . The danger with IR is, that IR light can´t be seen by your eye, so the protective lid-shutting reflex doesn´t work.

The IR light isn´t collimated as well as the green light by the laser optics and therefore spreads out quickly. The danger ist, that if you look head-on your laser, - with your eye beside the green dot of course - you might be still in the "radiation cone" of the IR light. Distance weakens the intensity of the IR light fast, so some distance reduce the danger. Diffuse reflections (like the "dot" on a surface) shouldn´t be dangerous, clear reflections only from short distances ... shining direct in the eye is a very bad idea ...

I thought I'd post some of the IR photos I attempted to take, these are both 10 second exposures aperture wide open using a DX 30 as the pointer and a nikon coolpix 5700 (with dieing pixels :mecryn CCD) and a hoya RM90 IR filter.
The first photo is taken at about 25cm with the beam reflecting directly into the lens. The second is taken with the beam terminating ~2.5 meters from the camera. I setup some obstacles in front of the camera to see If there was enough IR spilling out the side to illuminate them, I took another photo like the second with no laser being used to compare and the obstacles were illuminated exactly the same as with the laser (mostly due to the sunlight I assume).
Obviously this is a fairly unscientific method of measuring the IR output someone maybe able to interpret these photos better than me.


EDIT:: I probably should of posted these to as they show a comparison to a known IR emitting device (a TV remote to be precise). The first is the TV remote using the same setup as before pressing the button approximately once every second during the exposure (and waving the thing round like a madman to try and spread out the spots). The second photo is of the laser doing the same thing. In both cases the emitting device is held ~10cm from the lens and pointed directly at the camera.

I think Corona is being overly cautious (As you should be with any laser). But, I've seen other threads that have stated the DX lasers have very little IR leakage. Personally, I'm more worried about the potential damage done by the 30-50mw of green light.

I also think DX tends to take a CYA attitude toward its products. Whatever comment gets posted becomes the new description. No matter who you buy from it's always "Caveat Emptor".

Personally I'm enjoying my DX 30mw laser more than my Wicked 5mw. The wicked has a cleaner beam. (My DX seems to have more green spillage from the optics.) But the DX beam is more visible earlier in the evening and on moonlit nights compared to the Wicked.

As for legality, Just don't be a jerk. Law enforcement doesn't really care if you're pointing at stars or poping balloons. THEY DO care if you're sitting on the end of a runway or along a street at night shooting it into peoples cars, planes, or homes. Would I use it in public, no, It would seem like I'm showing off and the potential for problems is too great. In front of a small group that knows what I'm doing, sure, it's a great educational tool.

I work for law enforcement repairing their high-tech toys and the officers I shown it to all want to get one. (Come on, It's a frigg'in Buck Rogers laser for $30) Again, It all comes down to being responsible.

Thank-you guys! I just order mines. Can the beam of the 30mw be seen during the daylight? Can the 30mw Laser burn anything? I heard it can burn balloons....Though I'm not 100% sure.

LaserBeam110 said:

Thank-you guys! I just order mines. Can the beam of the 30mw be seen during the daylight? Can the 30mw Laser burn anything? I heard it can burn balloons....Though I'm not 100% sure.

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I have a DX 30mW, with mine no to all of the above.
Norm

Second, how can I know if my DX 30mw has a IR filter in it?

30mw DX has IR filter (reflective type which redirects IR beam 90 degrees from the main beam to photodiode which controls the overall output due to amount of IR) but it's not 100% effective. Do not worry about IR from DX 30mw, pay attention on what surface are you shinning on! Reflected green is your only concern. As for batteries, DX 30mw draws around 260-300mAh from AAA'a, so in real world, regular alkalines will not last 2 hours of use. Use lithium's, e2's or similar, for best result. And yes, it can pop black or red baloon from one foot. And be careful with carrying around, do not drop it on hard surface cause those little tiny optics and KTP are fragile to slightest displacement (the glue that is holding KTP to LD is not very good if you're playing football with it). Keep the optics safe from dust, it's hard to clean the lens cause it's hard approaching to it. Do not carry it in your pocket unless you make some sort of end-cap that will protect entering dirtiness from inside of your pocket.
And that's pretty much everything that is important for good laser/owner relationship. Stay cool.

brighter said:

30mw DX has IR filter (reflective type which redirects IR beam 90 degrees from the main beam to photodiode which controls the overall output due to amount of IR) but it's not 100% effective. Do not worry about IR from DX 30mw, pay attention on what surface are you shinning on! Reflected green is your only concern. As for batteries, DX 30mw draws around 260-300mAh from AAA'a, so in real world, regular alkalines will not last 2 hours of use. Use lithium's, e2's or similar, for best result. And yes, it can pop black or red baloon from one foot. And be careful with carrying around, do not drop it on hard surface cause those little tiny optics and KTP are fragile to slightest displacement (the glue that is holding KTP to LD is not very good if you're playing football with it). Keep the optics safe from dust, it's hard to clean the lens cause it's hard approaching to it. Do not carry it in your pocket unless you make some sort of end-cap that will protect entering dirtiness from inside of your pocket.
And that's pretty much everything that is important for good laser/owner relationship. Stay cool.

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Thank-you so much.

Here is a night shot from a Canon video camera of my 30mW DX that I just took.

It is sitting on a cardboard box projecting roughly parallel to the surface.

Would there be visible blooming in the image if there was a significant amount of IR present?

IR is invisible to the naked eye. Is your camera IR sensitive?

IR will only be visible to something capable of seeing it...and since it's not collimated (in a narrow beam) it spreads out and dissipates VERY fast.

-- Chuck Knight

chuck said:

IR is invisible to the naked eye. Is your camera IR sensitive?

IR will only be visible to something capable of seeing it...and since it's not collimated (in a narrow beam) it spreads out and dissipates VERY fast.

-- Chuck Knight

Click to expand...

That's why I mentioned it was a "night shot" type pic. I'm not certain if the video cameras with night shot capability will detect more IR or if it just pushes the sensor at the expense of noise/resolution.

It just dawned on me that I have access to a Fluke Ti20. It may answer the IR question.

Checked with the Fluke Ti20. Did not detect IR - the spectral range for the Ti20 is 7.5-14 microns. This should be outside the range expected from the laser.

However, it did detect the heat generated by the beam.