DX 30 mW CR2 Review - recommended laser!

A nice surpise in the mail: http://www.dealextreme.com/details.dx/sku.7883 30mW CR2 powered laser, $28.75

This review contains some comparisons to the very similar looking 50 mW CR2 from Kaidomain, but its not intended as a comparison between the two per se.

The laser came in a cardboard box with plastic inlay, a primary CR2 battery and a manual of sorts. In the picture it is next to the KD50, which is exactly the same size, but has a bit better paintjob (some copper shines through on edges with the DX). Also notice the DX has no lanyard, nor a hole to fit one. The warning labels are different too, though both contain the 'DRIECT' typo.

The unit is easily unscrewed revealing the electronics. The circuit board seems intended for a pen style laser with a switch on it, but is radically different from the one in either the KD50 or the DX pen style lasers.

It contains only 2 transistors, a few resistors and capactor. I'm guessing this is a basic 2-npn current source, and the pot only adjusts base drive for the main transtor to some degree. It performs reasonably well, though far from perfect: current draw is 450 mA from a 3.6V rechargeable, 410 mA from the supplied primary cell.

Note that this is much more than the KD50 which draws around 300 and 220 mA respectively.

Construction and circuit board closeups:

There seems to be metal connection between the laser diode, the tube it is in, and between the tube and the ring connecting the case parts. However, it seems something didnt quite fit and some paper was used on about half of the ring to make it fit snug. Despite this clumsy solution, heat is tranferred well, and electrical contact is also good - it works fine without the head.

Also notice: the focussing lens is glued in place with white goo.

Last but not least: Performance!

The beam from this laser is very similar in power and divergence to that of a (really really good) DX30 pen style laser. However, the CR2 comes on full power right away, while the AAA powered pen took over a minute to get this bright. At this point output is equal visually, and i have no means to measure it. I'd gauge it to be very close if not over the advertised 30 mW though.

Power output does go down visibly after a minute or two of operation, and the unit gets a bit warm. I am not sure yet if this is caused by battery sag or the temperature alone. But even after 5 minutes of ontime, it easily cuts thin plastic wrappings and such, so its by no means as bad as with many other lasers.

Only time will tell how long the unit lasts, but for now i'd say its worth is price!

Also, i'm inclined to recommend this laser over both the KD50/CR2 and the DX30/AAA, as it is better constructed that the first, and much more stable than the latter. Price for these laser is equal apart from some smallchange.

I posted the above last week before the server outage and data loss. I rescued the text from the google cache, and added the images back to it. I couldnt find any comments in the cache, so if you made one, please add it again.

As fas as dimming is concerned: I've tried with freshly charged batteries and it lasts at least 10 minutes at very good power on those. Dimming noticed before seems mostly due to battery sag, not thermal problems.

Thanks for reposting the review. Its most helpful.

I didn't know you already received it.. Glad i found this thread now.

Since you also have the KD50, how bright is this one in comparison?



Even if the regulation isn't perfect, it's still much better than in the KD50. That is actually a small difference in current, between a primary cell and a full (i guess?) 3.6V Li-Ion. On my KD50, the current would jump from 310 to 410mA and the diode died. Looks like this one uses a more powerful diode. Could finally be a good laser from a reliable supplier.. KD is starting to annoy me.

I received it a while back, but the review got first deleted with the server problems... so i recreated it from cache.

About the regulation: The package it comes in (brand: SXD) says:
- working voltage 3.0 - 4.2 V
- working current 250-550 mA
- working temperature +10 to +35 C

So i guess my measurements are well within specification and the manufacturer seems to have no problem with running it from a rechargeable at. I'm still surprised by the current though, way more than most 20-50mW greens take.

As far as brightness goes it'd say its about the same as the 'good' KD50 i had, but that died after a few days. For the pictures above i compared it to a AAA DX30 at its optimum temperature, and it is about the same.

Note that the AAA DX30 took over a minute to reach this power level, while the CR2 comes on immediately at full power and stays there too.

Nice... I need to order another laser..

If its as good as the one i got, its $29 well spent. Please post your experiences when you get one though, i wonder how consistent quality is with these units. I see its on backorder though, so it might take some time to get one.

Great Review Benm! I don't know if you remember, but I did a similar review, but w/o photos. Your review put mine to shame so I'm not going to bother with trying to recall mine from before the BLACKOUT! I really like mine & have ordered another, but like you posted earlier, it IS B/O'd But I DO agree, it's a well spent $29.00. My wife ordered both of these for me as kind of early Father's Day gifts :-?Gotta love that lady!!! :-* Phoenix77

phoenix77 said:

My wife ordered both of these for me as kind of early Father's Day gifts :-?Gotta love that lady!!! :-*

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Holy crap! Your wife ordered lasers for you? You lucky, lucky man! Put her on a big RPL-shaped pedestal and worship her like the goddess she is! ( but not too much... it goes to their heads y'know... )

Curiously_Coherent said:

Holy crap! Your wife ordered lasers for you? You lucky, lucky man! Put her on a big RPL-shaped pedestal and worship her like the goddess she is! ( but not too much... it goes to their heads y'know... )

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How do you think I got my DX200 red? Laser-friendly wives rule.

Does anyone know if it has an IR filter?

No, it does NOT have an IR filter. I do know that with the excellent heat-sink, that you can turn the 'pot' up pretty far & with a quick but careful adjustment to the collimating lens, that it will light RED-TIPPED matches, & pop balloons like nobodies business! I think they are WELL WORTH the $ that DX charges for them. I love mine :-* phoenix77

I think it could be able to light a match as it is with a focussing lens. I havent tried to yet, but when i shine in throuh a focussing lens, it defenitely smokes dark plastics and such around the focal point. As it also melts plastic readily without any extra lens, i'm sure popping balloons is possible.

I'm not sure exactly what the pot does, but it seems to regulate base drive for the current source. I'm rather hesitant to mess with it though, as it already draws so much current (450 mA) and i have no idea about the ratings of the pump diode.